C. V. Raman and the Discovery of the Raman Effect

Abstract

In 1928 the Indian physicist C. V. Raman (1888-1970) discovered the effect named after him virtually simultaneously with
the Russian physicists G. S. Landsberg (1890-1957) and L. I. Mandelstam (1879-1944). I first provide a biographical sketch
of Raman through his years in Calcutta (1907-1932) and Bangalore (after 1932). I then discuss his scientific work in acoustics,
astronomy, and optics up to 1928, including his views on Albert Einstein's light-quantum hypothesis and on Arthur Holly Compton's
discovery of the Compton effect, with particular reference to Compton's debate on it with William Duane in Toronto in 1924,
which Raman witnessed. I then examine Raman's discovery of the Raman effect and its reception among physicists. Finally, I
suggest reasons why Landsberg and Mandelstam did not share the Nobel Prize in Physics for 1930 with Raman.

Full text

Phys. perspect. 4 (2002) 399–420 © Birkha¨user Verlag, Basel, 2002
1422–6944/02/040399–22
C. V. Raman and the Discovery of the Raman
Effect*
Rajinder Singh**
In 1928 the Indian physicist C. V. Raman (1888–1970) discovered the effect named after him virtually
simultaneously with the Russian physicists G. S. Landsberg (1890–1957) and L. I. Mandelstam
(1879–1944). I first provide a biographical sketch of Raman through his years in Calcutta (1907–1932)
and Bangalore (after 1932). I then discuss his scientific work in acoustics, astronomy, and optics up to
1928, including his views on Albert Einstein’s light-quantum hypothesis and on Arthur Holly Compton’s
discovery of the Compton effect, with particular reference to Compton’s debate on it with William
Duane in Toronto in 1924, which Raman witnessed. I then examine Raman’s discovery of the Raman
effect and its reception among physicists. Finally, I suggest reasons why Landsberg and Mandelstam did
not share the Nobel Prize in Physics for 1930 with Raman.
Key words
:
Raman effect; Chandrasekhara Venkata Raman; Nobel Prize in
Physics; light scattering; Arthur Holly Compton; Compton effect; light quanta;
Albert Einstein; Arnold Sommerfeld; Adolf Smekal; Grigorii Samuilovich Lands-
berg; Leonid Isaakovich Mandelstam.
Introduction
In 1905 Albert Einstein (1879– 1955) proposed his revolutionary hypothesis of light
quanta, which in succeeding years was greeted by physicists with extreme skepti-
cism. Max Planck (1858– 1947) called it ‘‘a speculation that missed the target,’’ and
Robert A. Millikan (1868– 1953) said it was a ‘‘bold, not to say reckless hypothe-
sis.’’
1
It gained acceptance only after 1923, when Arthur Holly Compton (1892–
1962) discovered the Compton effect,
2
the change in wavelength of an X-ray
quantum when striking a free electron in a substance such as carbon in a
billiard-ball collision process.
Five years after Compton’s discovery, the Indian physicist Chandrasekhara
Venkata Raman (1888– 1970) and his student Kariamanikam Srinivasa Krishnan
(1898– 1961) discovered another effect involving a change in wavelength of scat-
tered monochromatic visible light. Probably because of its generality, the American
* This article is based on a talk I gave on December 16, 2000, at a Symposium on the Foundations
of Quantum Physics before 1935 in Berlin, Germany.
** Rajinder Singh is a Diplom-Physiker who is currently working on his doctoral thesis on C. V.
Raman and the discovery of the Raman effect in the Department of Higher Education and History
of Science in the Faculty of Physics at the University of Oldenburg, Germany.
399

R. Singh Phys. perspect.400
physicist Robert Williams Wood (1868– 1955), who was well known for his work in
experimental optics, hailed their discovery with the words: ‘‘It appears to me that
this very beautiful discovery, which resulted from Raman’s long and patient study
of phenomena of light scattering, is one of the most convincing proofs of the
quantum theory of light which we have at the present time.’’
3
In this paper, I first
provide a biographical sketch of Raman; I then discuss his scientific work before
the discovery of the Raman effect; and I finally comment on the reception of his
discovery by the scientific community at the time.
Chandrasekhara Venkata Raman
Chandrasekhara Venkata Raman (figure 1) was born on November 7, 1888, in a
village near Trichinopoly in the province of Tamil Nadhu, India.
4
His father
Chandrasekaran Aiyar was professor of mathematics and physics at the A.V.N.
College in Vizagapatam; his mother Parvati Ammal came from an educated family
known for its Sanskrit scholarship. Like his father, Raman played the violin
Fig. 1. Chandrasekhara Venkata Raman (1888 – 1970). Courtesy of the Raman Research Institute,
Bangalore.

Vol. 4 (2002) Raman and the Raman Effect 401
exceedingly well and was deeply interested in music and acoustics,
5
following in the
venerable tradition of Lord Rayleigh (1842– 1919) and Hermann von Helmholtz
(1821– 1894). In a symposium on Books That Ha6e Influenced Me Raman recalled:
Speaking of the modern world, the supremest figure, in my judgment is that of
Hermann von Helmholtz … . It was my great good fortune, while I was still a
student at college, to have possessed a copy of an English translation of his great
work on ‘‘The Sensations of Tone.’’ … It treats the subjects of music and musical
instruments not only with profound knowledge and insight, but also with
extreme clarity of language and expression. I discovered the book myself and
read it with the keenest interest and attention. It can be said without exaggera-
tion that it profoundly influenced my intellectual outlook. For the first time I
understood from its perusal what scientific research really meant, and how it
could be undertaken. I also gathered from it a variety of problems for research
which were later to occupy my attention and keep me busy for many years.
6
He continued: ‘‘Helmholtz had written yet another great masterpiece, ‘The physiol-
ogy of vision.’ Unfortunately, this was not available to me as it had not then been
translated into the English language.’’ Raman dedicated the last epoch of his life to
this topic and wrote a book of the same title.
7
Raman studied at his father’s college and at the Presidency College of the
University of Madras, where he received his B.A. degree in 1904 at the age of 16,
ranking first in his class and receiving a gold medal in physics. He received his M.A.
degree with the highest honors in January 1907. Meanwhile, in 1906, he had
published his first scientific paper, which was on diffraction and appeared in the
Philosophical Magazine.
8
He carried out further researches as a student but they
were not published for various reasons.
9
His teachers were greatly impressed with
him, remarking: ‘‘The best student I have had in thirty years’’; ‘‘A young man of
independence and strength of character’’; ‘‘Exhibited an unusual appreciation of
English literature and a facility in idiomatic expression’’; ‘‘Possessing great alertness
of mind and is strong intellectual.’’
10
His physics professor, R. L. Jones, especially
recognized Raman’s aptitude for research and urged him to go to England for
further studies. Jones sent him to Colonel Gifford for a physical checkup. Raman
recalled that Gifford ‘‘examined me and certified that I was going to die of
Tuberculosis … if I were to go to England.’’
11
Raman’s best choice for a good position was in the Indian Finance Department,
for which he had to take a special examination. He recalled about his examiners in
physics and economics: ‘‘I had such tremendous confidence in myself that I had not
the least difficulty in putting those gentlemen in their proper places. I made it clear
to Sir [Jagadis Chunder] Bose that I knew as much Physics as he did.’’
12
Such a
mixture of self-confidence, pride, and arrogance were part of his personality.
Raman placed first in this examination, as he always had in the past, and was
appointed as a bank officer in Calcutta in 1907. There he came into contact with
the Indian Association for the Cultivation of Sciences (IACS), which had been
established in 1876 for research purposes by Mahendralal Sircar (1833– 1904).
Raman became a member for life, and to make its work much better known, he
took the lead in bringing out its Bulletin and Proceedings, the latter of which was

R. Singh Phys. perspect.402
renamed in 1926 as the Indian Journal of Physics. His own research and outstanding
scientific abilities soon made him a popular figure among Calcutta’s educated elite.
Still, when the Palit Professorship of Physics at Calcutta University was established,
Raman was not the first choice for this position. Asutosh Mookerjee (1864– 1924),
a judge and Vice Chancellor of Calcutta University, wrote to the Viceroy of India
on June 29, 1912, that, ‘‘I am hoping to be able to secure Dr. J. C. Bose for the
Chair of Physics … .’’
13
This plan fell through for some reason, however, and in
1914 the Palit Professorship was offered to Raman.
Raman was reluctant to accept this position, because it carried a salary of only
600 rupees, about half of what he was making as a bank officer.
14
At this critical
time, his wife Lokasundri (1892– 1980), whom he had married in 1907, suggested
that he should not bother about this financial question and should accept the
professorship.
15
Before he did, he gave it careful consideration and imposed definite
conditions on his acceptance. On May 11, 1917, a letter in which he presented his
conditions was read at a meeting of the Syndicate of the University by its Secretary,
who reported that Raman had received permission to accept the Palit Professorship
and had requested to be informed if the University was prepared to sanction the
following conditions:
(a) House allowance of 250 rupees per mense [month] in addition to the salary
for the chair, so long as a suitable residence is not provided, (b) to declare that
his position in relation to teaching M.A. and M.Sc. students would be the same
as has been defined and accepted in the case of … [others]; (c) to formally
appoint him as Director of the Sir T. N. Palit Physical Laboratory to supervise
and control the physics staff working in the laboratory and also to be in sole
executive charge of all laboratory arrangements. Also suggested that a grant of
5000 rupees be placed at his disposal to enable him to arrange the first setting up
of his research laboratory.
16
Raman was not given full control of the laboratory, but all of his other conditions
were met.
The available documents show that as soon as Raman assumed the Palit
Professorship, conflicts arose. On August 30, 1917, Jagadis Chunder Bose (1858–
1937), who was Professor of Physics at Presidency College, Calcutta, and was well
known also for his work on plant physiology, wrote to the Vice Chancellor of
Calcutta University:
It has been reported to me that, on the 25
th
instant, a member of the Department
of Physics of the University College of Science called at my Laboratory at the
Presidency College during my absence, and with special instructions from Prof.
Raman to invite my senior mechanic to transfer his services to the College of
Science Physical Department, with offer of increased salary above what he gets
from me … even up to three times if necessary … . I must, therefore, formally
express to the University my regret … .
17
There also are reports about a dispute that Raman had with the Indian astrophysi-
cist Meghnad Saha (1894– 1956) regarding the use of the laboratory.
18
Parochialism
too played a role, with Raman being considered as an ‘‘outsider.’’ For instance, in

Vol. 4 (2002) Raman and the Raman Effect 403
one of his letters Saha wrote to a student, Pratap K. Kichlu, that: ‘‘When you
submit [your] thesis for [the] D.Sc. . . the examiners ought to be Professor [Ralph
H.] Fowler, Lord Rayleigh and myself. Do not allow Raman or [John W.]
Nicholson to be put in. It is time that the Committee of Courses in Physics should
insist on an internal man.’’
19
On the whole, however, Raman’s relations with other
Bengalis, and in particular with Saha, remained collegial until 1933. In 1931, for
example, Raman wrote a reasonably good Foreword to the first edition of Saha’s
book on heat.
20
Raman’s activities extended beyond Calcutta University. In 1914 the Indian
Science Congress (ISC) was founded (it was renamed the ISC Association in 1935)
on the model of the British Association for the Advancement of Science, and from
1915 to 1921 two of its founders, J. L. Simonsen and P. S. McMohan, who were
British professors working in India, served as its secretaries, while subsequently
Indian scientists like Raman and the plant morphologist Shankar P. Agharker
(1884– 1960) also held this position.
21
In 1919 Raman also became honorary
secretary of the Indian Association for the Cultivation of Science (IACS),
22
and at
the end of 1922 he was proposed for membership on the Council of the Asiatic
Society of Bengal (founded in 1784 by William Jones) and was elected to it the
following year.
23
Raman also held various positions in the Astronomical Society of
India (see below).
Until 1917 Raman carried out his researches almost single-handedly. Then, after
he became Palit Professor, he was allowed to use the Calcutta University laborato-
ries, but he still worked mostly at the IACS. His researches on acoustics and optics
brought him high recognition. In November 1921 he was proposed for election as
a Fellow of the Royal Society of London. His nomination certificate reads:
Although trained entirely in India, [Raman] has made considerable additions to
our knowledge of sound and light, having published about fifty memoirs. The
chief are: Experimental Investigations on the Maintenance of Vibration; The
Dynamical Theory of Bowed Strings; Vibrations of Bowed Strings and of
Musical Instruments of the Violin Family; On Kaufmann’s Theory of the
Pianoforte Hammer; … . Photometric Measurement of the Obliquity Factor of
Diffraction; The Curvature of Lines in Diffraction Spectra;... The Diffraction
Figures due to an Elliptic Aperture; The Colours of Mixed Plates.
24
Raman was elected FRS on May 15, 1924.
The highest honor Raman received was the Nobel Prize in Physics for 1930 for
his work on the scattering of light, particularly for his discovery of the effect named
after him. In 1933 he accepted the directorship of the Indian Institute of Sciences
(IIS) in Bangalore, evidently with some hesitation according to unpublished bio-
graphical documents of his predecessor, Sir Martin O. Forster, FRS (1872– 1945).
In Calcutta Raman was in the prime of his life and was feeling well; in Bangalore
he soon became involved in both scientific and personal controversies. After 1933,
three major incidents in his scientific life occurred that made him a controversial
and bitter person. First, a group of people in Calcutta had the feeling that Raman,
who was now living in Bangalore, still controlled the affairs of the IACS and
wanted to change its constitution in regard to its provision for lifetime membership.

R. Singh Phys. perspect.404
According to its statutes, any person who donated 500 rupees could become a
member for life, whereas Raman wanted to place the decision for granting lifetime
membership in the hands of a managing committee. Before Raman could change
the constitution accordingly, word of his plan leaked out and was exploited by a
local newspaper,
25
forcing Raman, who had been a member of the IACS for 25
years, to leave the Association in disgrace. Second, a committee was formed to
explore the establishment of a scientific academy on the model of the Royal Society
of London. Raman was one of the committee members, but before its final meeting
he resigned and personally established the Indian Academy of Sciences in 1934,
26
which made him exceedingly unpopular in some circles. Third, owing to various
disputes with the staff and members of the Council of the Indian Institute of
Sciences (IIS) in Bangalore, he was forced to resign as its director in 1937.
After his resignation as director, Raman remained as Professor and Head of the
Department of Physics of the IIS until his retirement in 1948. He then built a new
institute for himself in a suburb of Bangalore (today it is known as the Raman
Research Institute) where he worked with half a dozen students during the
following decade, making significant contributions to the fields of crystal physics,
crystal optics, and mineralogy. During the last ten years of his life he worked
without any students or assistants.
27
He remained President of the Indian Academy
of Sciences in Bangalore and Director of the Raman Research Institute until his
death in 1970.
Raman’s Scientific Work up to 1928
Raman as Palit Professor founded what became known as the Calcutta School of
Physics. His scientific fame attracted students and researchers from all corners of
India to work under him. As the Indian historian S. N. Sen noted, ‘‘During the year
1928, Prof. Raman had under him in the laboratories of the Association [IACS] 32
research workers, of whom 21 were whole-time workers and 11 worked part-time.
The number of research workers in the Palit Laboratory of Physics at the [Calcutta]
University College of Science is not known.’’
28
By 1938, a decade later, around 80
positions, mostly in universities and colleges, were occupied by Raman’s former
students or collaborators.
29
Prior to 1921, when his research took a new turn as we
shall see, he and his students worked mostly in three fields, acoustics, astronomy,
and optics.
Acoustics
Although Raman is known today mostly for his work on the scattering of light, he
also carried out significant researches in acoustics. In a recent review of the
non-linear physics of musical instruments, N. H. Fletcher wrote: ‘‘Musical instru-
ments have been of interest to scientists from the time of Pythagoras, 2500 years
ago, and since then many famous physicists, among them Helmholtz, Rayleigh and
Raman, have devoted at least some of their attention to them.’’
30
That Raman was

Vol. 4 (2002) Raman and the Raman Effect 405
mentioned in the same breath with Helmholtz and Rayleigh leaves no doubt about
the importance of his work. His researches on musical instruments have continued
to attract attention in the 1990s.
31
One of Raman’s masterpieces was his monograph of 1918, ‘‘On the Mechanical
Theory of the Vibrations of Bowed Strings and of Musical Instruments of the
Violin Family.’’
32
Earlier, his work had attracted favorable attention both in
England
33
and in Germany. Regarding the latter, S. N. Sen has observed that:
‘‘Raman’s investigations on the maintenance of vibrations were noticed with
appreciation by Prof. Alfred Kala¨hne … in the Proceedings of the German Physical
Society in the November issue of 1914 in connection with his review of Helmholtz’s
theory of forced vibrations of a string.’’
34
A dozen years later, Raman was the only
non-European who was invited to contribute an article to the famous Handbuch der
Physik.
35
His contribution, ‘‘Musikinstrumente und ihre Kla¨nge’’ (‘‘Musical Instru-
ments and their Tones’’), dealt with the physical characteristics of the musical tones
emitted by string, wind, and percussion instruments.
36
In an earlier chapter in the
same volume of the Handbuch, the work of Raman and his collaborators was cited
extensively.
37
Astronomy
Raman’s interest in astronomy seems to have escaped the attention of his biogra-
phers. It was associated with the founding of the Astronomical Society of India
(ASI) in 1910 in connection with the observation of Halley’s Comet.
38
In 1911
Raman was elected as a member of the ASI, and he later held various offices in it,
such as Secretary of Business, Honorary Secretary, and Director of the Variable
Star Section.
39
He also delivered popular lectures at meetings of the ASI, which
were published in the Society’s journal, and which dealt with diffraction and
interference phenomena in telescopes and astronomical observations he made with
them.
40
Thus, he made observations of a lunar eclipse, of Venus, and of the
satellites of Jupiter with a small telescope, and later with a somewhat larger one.
41
His name was carried as an elected member of the Council of the ASI until
1919– 1920, although a study of the Society’s journal reveals that his active work in
astronomy ceased in 1916 for practical reasons,
42
namely, because he could not
afford to purchase a powerful telescope and locate a proper site to make
observations.
43
Optics
Beginning in 1921, Raman began to concentrate on a new topic, optics, and during
the next two years he published 42 papers on this subject, some with coauthors.
44
During 1922 most of his work was related to the scattering of light in liquids,
vapors, and gases. His two major contributions that year were, first, writing a
monograph, Molecular Diffraction of Light,
45
that summarized various work and,
second, proposing an explanation of the blue color of the sea, which I will discuss
below.

R. Singh Phys. perspect.406
Fig. 2. Canal rays at K travel perpendicular to the optical axis of lens L1 and through one of its focal
points, the other one being at a slit in the screen S. The light emitted by the canal rays then enters lens
L2, is collimated, and enters telescope T.
In 1923 Raman turned to X-ray scattering, but during 1923– 1924 he published
only four papers on this subject and then interrupted this work for almost three
years,
46
very likely because he realized that he needed expert help in this field. Thus,
during this period he established contact with the Swedish experimental physicist
Manne Siegbahn (1886– 1978) and the Danish theoretical physicist Niels Bohr
(1885– 1962), asking them to take on one of his former students, Bidhu Bhushan
Ray (1894– 1944), and train him in this field.
47
Ray spent six months with Siegbahn
in Uppsala and a year and a half with Bohr in Copenhagen (October 1924– Febru-
ary 1926).
48
After returning home, however, Ray and Raman for some reason went
their separate ways, coauthoring no papers together.
Raman and Light Quanta*
Raman’s first two publications that were directly related to Einstein’s light-quan-
tum concept appeared in 1922.
49
They were in response to Einstein’s proposal in
December 1921 of an experiment that should be able to decide between the wave
and quantum natures of light.
50
Einstein’s proposed experiment is illustrated in
figure 2, where canal rays (positive ions) travel perpendicular to the optical axis of
lens L1 and through one of its focal points, the other one being at a small slit in
screen S. Thus, any light that is emitted by the canal rays passes through the slit in
screen S, enters the lens L2, is collimated, and then enters the telescope T. Since the
canal rays are moving, however, the light they emit, if it consists of waves, should
be Doppler-shifted, and indeed in such a way that its wavelength when leaving lens
L2 should be greater at the top of the beam than at the bottom. If a dispersive
medium is then placed between lens L2 and the telescope T, the beam of light
* This and the following section are based largely on my article, ‘‘The Indian Trio: S. N. Bose, C. V.
Raman and M. N. Saha, and the Light Quanta,’’ in International Symposium on the Centenary of
Planck
’
s Law
:
Rele6ance in Science and Technology (Calcutta, December 14–16, 2000), pp. 25–39.

Vol. 4 (2002) Raman and the Raman Effect 407
should be deviated slightly, so that the image of the slit as seen in the telescope
should be shifted somewhat, by an amount that is proportional to the thickness of
the dispersive medium. By contrast, if the canal rays were emitting light quanta,
that light should be monochromatic and hence should not be either Doppler-shifted
or deviated. On Einstein’s insistence, Hans Geiger (1882– 1945) and Walther Bothe
(1891– 1957) in the Imperial Physical-Technical Institute (Physikalisch -Technische
Reichsanstalt) in Berlin-Charlottenburg performed this experiment and found no
deviation in the beam of light. Their result was discussed intensely by Einstein with
Arnold Sommerfeld (1868– 1951), Max von Laue (1879 – 1960), and Paul Ehrenfest
(1880– 1933). Ehrenfest finally convinced Einstein at the end of January 1922 that
this experiment did not constitute a crucial test, after all, between the wave and
quantum theories of light.
51
Raman, far away from Europe in India, had no knowledge of these discussions.
He read Einstein’s article a few weeks after Ehrenfest, in fact, had settled the issue.
But he came to a similar conclusion. In two short articles he suggested that
Einstein’s experiment could not discriminate between the two theories of light,
because when the light is diffracted by the various components of the instrument no
Doppler shift was to be expected.
52
In 1922 Raman also argued that the Einstein-Smoluchowski formula, which is
based on the electromagnetic wave theory, and which expresses the scattering power
of a medium in terms of its compressibility and refractive index but does not take
into consideration the molecular structure of the medium, is qualitatively invalid,
because under certain conditions the scattering falls off much more rapidly than
predicted.
53
He suggested that one should apply instead the quantum theory of light
to explain molecular diffraction. Indeed, in chapter 9 of his monograph, Molecular
Diffraction of Light, Raman noted the success of Einstein’s light-quantum hypoth-
esis in explaining the photoelectric effect and the ionization of gases by X rays.
54
However, in the end he did not take a definite position on the nature of light but
said that experiments were underway in his laboratory to determine it.
Raman’s Work on the Scattering of Light
In the early 1920s, Raman devoted increased attention to the scattering of light and
discontinued his work on acoustics and astronomy. His major motivation appar-
ently was to challenge and reject Lord Rayleigh’s theory of the blue color of the
sea. In the second half of the nineteenth century, scientists had established
experimentally that small particles scatter light of bluish color and that this
scattered light is polarized.
55
In 1899 Rayleigh pointed out that the blue color of the
sky is due to the scattering of light by air molecules in the atmosphere.
56
He showed
that the scattering power is inversely proportional to the fourth power of the
wavelength, so that the short wavelengths in the visible spectrum of the sun’s light,
that is, the blue wavelengths, give the sky its color. A dozen years later, Rayleigh
also concluded that the blue color of the sea has nothing to do with the color of
water, but is simply the blue of the sky as seen by reflection.
57
Raman read this
paper of Rayleigh’s in Volume 5 of his Scientific Papers and in 1922 disproved

R. Singh Phys. perspect.408
Rayleigh’s idea, showing that the blue color of the sea is caused by the diffraction
of light by water molecules.
58
For this he made use of the Einstein-Smoluchowski
formula and found that the scattering power of a medium, in this case sea water,
also varies inversely with the fourth power of the wavelength, thus giving the sea its
blue color.
Raman’s concern with the nature of light also led him to study experimentally
how light is scattered in liquids and crystals and to determine its dependence on the
frequency of the light.
59
He further studied the scattering of light in dense vapors
and gases, finding that it was not completely polarized as was predicted by theory.
60
The French physicist J. Cabannes suggested that the isotropy of the molecules
should be taken into account, while Raman (figure 3) focused on the orientation of
the molecules in liquids, developing a qualitative theory that in some cases was able
to account for the observed polarization.
61
One of Raman’s collaborators, Kalpathi Ramakrishna Ramanathan (1893–
1985), also carried out experiments that Raman later interpreted as crucial to his
discovery of the Raman effect. Ramanathan studied the intensity of light scattered
by liquids and observed that it was in agreement with theory for moderately
anisotropic molecules (water, ethyl alcohol), while it diverged from theory for
strongly anisotropic molecules (ether, benzene, toluene).
62
These results led him to
examine how the polarization of the scattered light depends on its wavelength,
leading him to remark: ‘‘Incidentally it is shown that a change previously observed
in the imperfection of polarisation with water and alcohol is due to the presence of
atrace of fluorescence [emphasis added].’’
63
Further, ‘‘The origin of the fluorescence
Fig. 3. Chandrasekhara Venkata Raman (1888 – 1970). Courtesy of the Raman Research Institute,
Bangalore.

Vol. 4 (2002) Raman and the Raman Effect 409
has yet not been definitely ascertained … . In spite of many redistillations, the effect
remained practically undiminished.’’
Raman’s use of the term ‘‘trace of fluorescence,’’ or ‘‘feeble fluorescence,’’
64
was
directly related to the work of Arthur Holly Compton. As Raman stated later in a
lecture to the Faraday Society:
It will be recalled that Compton was inclined to attribute the softening of X-rays
by scattering to what he called ‘‘a general fluorescent radiation’’ until his
spectroscopic investigations gave an entirely different version of the matter. It is
not surprising, therefore, that the optical effect brought into evidence by the
Calcutta investigations was also labeled as a ‘‘special type of feeble
fluorescence.’’
65
Raman and the Compton Effect
In August 1924, Arthur Holly Compton, more than a year after he discovered the
Compton effect at Washington University in St. Louis, Missouri, and moved to the
University of Chicago, engaged in a second debate with William Duane of Harvard
University on the validity of the Compton effect at a meeting of the British
Association for the Advancement of Science (BAAS) in Toronto. Raman was
present at this debate, and following it, Compton recalled that Raman said to him,
‘‘Compton, you’re a very good debater; but the truth isn’t in you.’’
66
Raman’s
statement has been interpreted by Roger H. Stuewer and A. Sur as evidence for
Raman’s resistence to accept the Compton effect as proof of the validity of
Einstein’s light-quantum hypothesis.
67
In this section, I will examine the circum-
stances under which Raman made this statement and show that it cannot be
interpreted as opposition to Compton’s discovery. I thus will show that well before
Raman discovered the Raman effect he accepted the quantum nature of light.
At the BAAS meeting in Toronto, William Duane gave a paper entitled, ‘‘On
Secondary and Tertiary Radiation,’’
68
in which he reported on experiments that he
had carried out with Samuel K. Allison, George L. Clark, and William W. Stifler
at Harvard. Duane argued that the change in wavelength that Compton had
observed ‘‘must be due to fluorescent radiation generated in the crystal itself by
X-rays of much shorter wave-lengths.’’ He thus opposed Compton’s quantum
interpretation and attributed the change in wavelength to a secondary effect.
Eventually however, after Compton visited Duane’s laboratory, Duane changed his
mind and accepted Compton’s experimental results and interpretation.
69
Compton also gave a paper at the Toronto BAAS meeting entitled, ‘‘The
Quantum Theory of the Scattering of X-rays,’’
70
whose content is evident although
there is no abstract or summary of it in the report of the meeting. Joseph A. Gray
also gave a paper entitled, ‘‘Scattering of X- and Gamma-rays and the Production
of Tertiary X-rays,’’ in which he argued that: ‘‘Experiments with X-rays show that
the proportion of scattered rays of longer wave-length than the primary is indepen-
dent of the crystalline structure and thickness of the radiator … . Results of the

R. Singh Phys. perspect.410
scattering of k-rays do not altogether agree with the quantum theory of scatter-
ing … . If X-rays consist of quanta, they should have a range. If this is the case, in
the writer’s opinion the wa6e theory should be abandoned [emphasis added].’’
71
The
reporter for Nature did not note a similar attitude on Compton’s part,
72
nor did
Compton argue for the abandonment of the wave theory in his original paper.
Rather, he hoped for a reconciliation of the wave and quantum theories of light,
noting that ‘‘the problem of scattering is so closely allied with those of reflection
and interference that a study of the problem may very possibly shed some light
upon the difficult question of the relation between interference and the quantum
theory.’’
73
Like Compton, Raman was impressed with the past success of the electromag-
netic wave theory in explaining interference and diffraction phenomena. Thus, at
the BAAS meeting, according to the reporter for Nature, Raman made an ‘‘elo-
quent appeal against a too hasty abandonment of the classical theory of light.’’
74
In
general, Raman believed that ‘‘theories must stand or fall according to as they
agree with the facts, and not vice versa,’’
75
and since Compton’s quantum theory of
scattering agreed with the experimental facts, Raman would not have objected to it.
How then can we explain the contrary recollections of Compton? Certainly he
would have been fascinated with Raman as one of the very few non-European
physicists present at the Toronto meeting, and wearing a turban too. As we shall
see, however, he evidently misinterpreted Raman’s remark: Raman’s objections
were not directed against light quanta or Compton’s experiments but were of a
more technical nature.
Thus, in 1927, Raman discussed Compton’s discovery and his recently published
book, X-Rays and Electrons, as follows:
As is well known, there is an addition to the X-ray scattering of degraded
frequency, an unmodified secondary radiation the existence of which has
been explained by Prof. Compton as due to the whole group of electrons in
the atom scattering conjointly. To this view, the objection might be raised that
if one electron acting alone can scatter a quantum, and also all the Zelectrons
in the atom acting together, then why do we not observe scattering by two,
three, or more electrons acting together at a time, with their corresponding
fractional Compton shifts in wavelength? To the alternative explanation of
the unmodified scattering given by Profs. Compton and [George E. M.] Jauncey
that it represents the scattering by an electron which the impinging quantum
is unable to detach from the atom, the equally pertinent query may be asked,
then why is the intensity of this type of radiation proportional to Z
2
and not to
Z?
76
Raman went on to emphasize the success of Maxwell’s theory in explaining
interference and scattering of light by solids, liquids, and gases under a wide range
of conditions, and then asked, as he had at the Toronto BAAS meeting, ‘‘Is it
conceivable … that Maxwell’s theory and thermodynamics taken together would
fail in the closely allied field of X-ray research?’’
77
Thus, Raman sought to explain
the Compton effect classically, and indeed in 1928 he derived the change in

Vol. 4 (2002) Raman and the Raman Effect 411
wavelength on the basis of the classical wave theory.
78
Moreover, he and C. M.
Sogani constructed an absorption photometer to study the Compton effect experi-
mentally,
79
which also leaves no doubt that Raman accepted Compton’s results
before he discovered the Raman effect.
Let us therefore revisit the Compton-Raman episode at the Toronto BAAS
meeting in 1924. Compton referred to it in his ‘‘Personal Reminiscences,’’ which
were published in 1967, five years after his death. He there recalled his debate with
Duane, noting:
After discussing it for a solid afternoon, we decided to call the debate a draw.
The result was summarized by a comment of C. V. Raman, who was visiting
Toronto at the time. As we left, he said to me, ‘‘Compton, you’re a very good
debater; but the truth isn’t in you.’’
80
Compton added: ‘‘I think it was probably these discussions that led him to discover
the Raman effect two year later, which was essentially a very similar phenomenon
that was observed in the field of light.’’ That Compton thus gives the year of
Raman’s discovery as 1926 instead of 1928 suggests that we should treat his
recollections cautiously.
This is supported by the somewhat different recollection of the Compton-Raman
episode by Compton’s wife, Betty McCloskey Compton. In an interview in 1968,
although she could not at first remember Raman’s name, she stated:
Anyway he [Raman] was very dark, just as black as could be, but he had a
beautiful Scotch accent. He would be asking questions from the back of the hall,
and it was so disconcerting to have this person, black as coal, with this beautiful
Scotch accent. He was the one who said, ‘‘Compton, you answer questions well;
you’re a good debater, but the truth isn’t in you.’’
81
When she then was asked if Compton had won the debate, she replied:
No, it was nip and tuck at that time. Raman had said, ‘‘well, you seem to be able
to answer the questions but I don’t believe it.’’ Afterwards he practically apolo-
gized for that. He said, ‘‘Oh Compton,that was in the heat of the discussion.I
really didn
’
t mean that [emphasis added].’’
82
Thus, the extent to which Raman opposed Compton in Toronto is uncertain. We
do know, however, that Compton’s winning of the Nobel Prize in 1927 was a
crucial stimulous to Raman. As Raman noted shortly after he discovered the
Raman effect in 1928:
Early this year … a powerful impetus to further research was provided when I
conceived the idea that the effect [I just discovered] was some kind of optical
analogue to the type of X-ray scattering discovered by Prof. Compton, for which
he recently received the Nobel Prize in Physics. I immediately undertook an
experimental re-examination of the subject in collaboration with Mr. K. S.
Krishnan and this has proved very fruitful in results.
83

R. Singh Phys. perspect.412
The Discovery of the Raman Effect
The velocity of light in a medium depends upon its index of refraction, which in
turn depends upon the wavelength of the light, a process known as dispersion. In
1922 the English theoretical physicist Charles G. Darwin (1887– 1962) attempted to
explain dispersion, unsuccessfully, on the basis of quantum theory.
84
The following
year the Austrian theoretical physicist Adolf Smekal (1895– 1959) assumed that
light has a quantum structure and showed that scattered monochromatic light
would consist of its original wavelength as well as of higher and lower wave-
lengths.
85
He derived a dispersion formula by exploiting Bohr’s correspondence
principle, that is, by assuming that the dispersion produced by an atom in a high
quantum state is the same in both the classical and quantum theories. Only in
1924– 1925 was a full and satisfactory quantum-theoretical explanation of disper-
sion provided by Hendrik A. Kramers (1894– 1952) and by Kramers and Werner
Heisenberg (1901– 1976), which formed the immediate background to Heisenberg’s
discovery of matrix mechanics.
86
Other prominent physicists also contributed to the
understanding of dispersion at this time.
87
Nevertheless, none of this theoretical
work, and in particular Smekal’s prediction of the appearance of higher and lower
wavelengths when monochromatic light is scattered, exerted a direct influence on
the discovery of the Raman effect.
Evidence for such an effect was published in July 1928 by the Russian physicists
Grigorii Samuilovich Landsberg (1890– 1957) and Leonid Isaakovich Mandelstam
(1879– 1944),
88
who were studying Albert Einstein’s and Peter Debye’s theories of
the specific heats of solids. They concluded that when light of frequency wis
scattered by a crystal, it would not only be diffracted by the Debye elastic waves
acting as a grating, it also would experience a frequency shift Dwcaused by the
elastic waves propagating at the velocity of sound. Searching for this frequency
shift in quartz, they observed that it was different from what they had expected,
which they took to mean that they had discovered a new phenomenon. They were
uncertain of its explanation, however. One possibility was that while being scat-
tered, the light lost energy by exciting infrared frequencies in the quartz crystal,
thereby diminishing the frequency of the light.
In India, Raman and K. S. Krishnan made their discovery while searching for an
optical analogue of the Compton effect. Raman noted in his first report
89
that in
1922 he and his student K. Seshagiri Rao had observed the depolarization of water
as a function of wavelength, which changed, for example, by 13.2, 10.2, 11.5, 15.3,
and 21.7 percent for red, yellow, green, blue, and violet light. Three years later, K.
S. Krishnan observed, as K. R. Ramanathan had before him, a ‘‘feeble fluores-
cence’’ when light was scattered by various liquids (water, ether, monohydric
alcohols, benzyl and benzol chlorides, methyl ethyl ketone, diethyl ketone, butyric
acid, and acetaldehyde).
90
Attempts to determine the spectrum of this ‘‘feeble
fluorescence’’ during the following years failed, because its intensity was too low.
91
(Recent experiments with a laser have shown that only a tiny fraction of light, 1
part in 10
8
, experiences a change in frequency when scattered.
92
) Thus, in the event,
very long exposure times were required to take spectra. The Russian physicists, for
example, reported exposure times of 2 to 14 hours and 100 hours under different

Vol. 4 (2002) Raman and the Raman Effect 413
Fig. 4. The first spectra taken by C. V. Raman and K. S. Krishnan. The upper-left photograph shows
the incident light consisting of the spectrum of a quartz mercury arc lamp after passing through a blue
filter that cuts out all wavelengths greater than the indigo line at 4358 A
,
ngstroms. The upper-right
photograph shows the same spectrum when scattered by liquid benzene and taken with a small Adam
Hilger spectroscope. Note the appearance of modified lines owing to the Raman effect. The lower-left
and the lower-right photographs show the same effect using a different filter. Courtesy of the Raman
Research Institute, Bangalore.
conditions for crystals.
93
Later, for vapors, exposure times of more than 180 hours
were required.
94
Raman first displayed spectra showing a change of frequency
during a lecture he gave at a meeting of the South Indian Scientists Association on
March 16, 1928 (figure 4).
95
In all, he and Krishnan had observed scattered
secondary radiation of smaller frequency in 60 liquids and vapors.
96
Because the
scattered light was of relatively high intensity and was polarized, they could rule
out the possibility that it was fluorescent radiation.

R. Singh Phys. perspect.414
Prior to the above lecture, Raman sent two short articles to Nature (one written
jointly with Krishnan),
97
which he signed on February 16 and March 8, 1928,
respectively, and which appeared in print before the first publication of the Russian
physicists, which was communicated to Die Naturwissenschaften on May 6, 1928,
and appeared in July 1928.
98
Raman’s articles in Nature did not display any spectra;
they first appeared in print when his lecture of March 16, 1928, was published in the
Indian Journal of Physics.
99
He sent reprints of that article reporting his discovery
to 2000 scientists in France, Germany, Russia, Canada, and the United States.
100
Reception
The first person to take note of Raman’s discovery was the French scientist Yves
Rocard (1903– 1992), who published a paper on it in the April 23, 1928, issue of the
Comptes rendus of the Acade´mie des Sciences.
101
In Germany, it seems that Raman’s
discovery was known only through Raman’s short articles in Nature and not
through his article in the Indian Journal of Physics that contained his spectra, which
led to some speculation about his discovery. Thus, the German theoretical physicist
Georg Joos (1894– 1959) wrote from Jena to Arnold Sommerfeld in Munich on May
14, 1928, asking, ‘‘Do you think that Raman’s work on the optical Compton effect
in liquids is reliable? … The sharpness of the scattered lines in liquids seems doubtful
to me.’’
102
Although Raman’s experiments could not be repeated successfully in
Munich, Sommerfeld (figure 5) nevertheless replied to Joos on June 9, 1928, that:
‘‘In my opinion Raman is correct … . He writes to me, that the difference between
the lines is exactly equal to the infrared frequencies of the molecules under
consideration.’’
103
In Berlin, the German experimental physicist Peter Pringsheim (1881– 1963)
repeated Raman’s experiments successfully and sent his spectra to Sommerfeld on
June 20, 1928, thus vindicating Sommerfeld’s belief in the validity of Raman’s work.
Pringsheim then reported his work in two articles the following month,
104
becoming
the first person to coin the terms ‘‘Raman effect’’ and ‘‘Raman lines.’’ In 1929
Pringsheim contributed an article on the Raman effect to the Handbuch der
Physik,
105
just as Joos contributed one to the Handbuch der Experimentalphysik.
106
In 1930 Clemens Scha¨fer and Frank Matossi contributed yet another article on the
Raman effect to the Fortschritte der Chemie,Physik und Physikalische Chemie,
107
here emphasizing its importance for chemistry. In 1931, K. W. F. Kohlrausch
published a book that contained 417 references on what he called, perhaps
chauvinistically, the Smekal-Raman effect.
108
Most of the papers that were pub-
lished on the Raman effect between 1928 and 1937 were published in Germany and
Austria.
109
The Nobel Prize
Raman received the Nobel Prize in Physics for 1930 ‘‘for his work on the scattering
of light and for the discovery of the effect named after him.’’
110
He received the

Vol. 4 (2002) Raman and the Raman Effect 415
Nobel Prize only two years after he made the discovery, and he was the first Asian
to be so honored. There seems to be three major reasons why the Russian
physicists, Landsberg and Mandelstam, did not share the Nobel Prize with Raman,
even though they discovered the effect almost simultaneously with Raman.
111
First,
no less than ten physicists from several countries nominated Raman for the Nobel
Prize, while only two Russians nominated Landsberg and Mandelstam for it. Thus,
the scientific community at large credited Raman with the discovery. Second,
Raman published his results earlier than the Russians, who in fact cited Raman’s
work, so that the Nobel Committee did not believe that the Russians had obtained
their results independently. Third, the Nobel Committee felt that Raman’s experi-
ments, since they involved solids, liquids, and gases, had established the universality
of the effect.
112
Conclusions
I have shown that Raman initiated experiments as early as 1922 in an attempt to
determine if light was of a wave or a quantum nature. He interpreted his results
successfully in terms of the Einstein-Smoluchowski formula, which was based on
Maxwell’s electromagnetic wave theory, and which led him to believe that there was
Fig. 5. Arnold Sommerfeld (middle) visited the Indian Association for the Cultivation of Science in
Calcutta in October 1928 and posed with K. S. Krishnan (left) and C. V. Raman (right). Courtesy of the
Raman Research Institute, Bangalore.

R. Singh Phys. perspect.416
no need to abandon that theory. I then argued that Raman did not object to
Compton’s discovery of the Compton effect because Compton interpreted it on the
basis of light quanta, but for more technical reasons. Raman’s remarks to Compton
at the BAAS meeting in Toronto in 1924 thus should not be interpreted as
resistance to Einstein’s light-quantum concept, even though Raman later derived
the Compton wavelength shift on the basis of the electromagnetic wave theory.
Raman’s work on light scattering led him to his discovery of the Raman effect,
which then was seen as a confirmation of Smekal’s prediction that when monochro-
matic light is scattered by a transparent medium the scattered light will also contain
both higher and lower frequencies. In general, Raman, like other Indian scientists,
worked in isolation and had to rely largely on his own knowledge and experiments.
In Germany, Sommerfeld accepted Raman’s discovery, and Pringsheim repeated
Raman’s experiments successfully, which overcame skepticism towards Raman’s
results. In the end, Raman was accorded priority for the discovery over the
Russians Landsberg and Mandelstam, and a large number of physicists nominated
him for the Nobel Prize in Physics for 1930.
Acknowledgments
I thank Falk Riess, University of Oldenburg, for valuable discussions and help with
this article. I am grateful to Roger H. Stuewer for valuable comments on an early
version of this paper and for his careful editorial work on it. I thank the following
institutions and individuals for sources on which this article is based: the American
Institute of Physics for Betty McCloskey Compton’s interview; the Asiatic Society
of Bengal for Raman’s correspondence; the Indian Institute of Astrophysics (D. C.
V. Mallik) for the Journal of the Astronomical Society of India; the Deutsches
Museum in Munich for Sommerfeld’s letters; Churchill College, Cambridge, for A.
Mookerjee’s letter; the Nehru Memorial Library in Delhi for Saha’s correspon-
dence; the Niels Bohr Archive in Copenhagen for Raman’s letter; the Raman
Research Institute for photographs, newspaper clippings, and Raman’s convocation
lecture; and the Royal Society of London for Raman’s nomination letter and M. O.
Foster’s document. I am obliged to a well-wisher (who desires to remain anony-
mous) for a copy of Bose’s letter. I am thankful to Santimay Chatterjee, Calcutta,
who sent me articles from The Illustrated Weekly of India and the Indian Physical
Society –Diamond Jubilee. Finally, I am grateful to the Heinrich Bo¨ll Stiftung in
Berlin for financial support while writing this article.
References
1 Quoted in Helge Kragh, Quantum Generations
:
A History of Physics in the Twentieth Century
(Princeton: Princeton University Press, 1999), p. 68.
2 Arthur H. Compton, ‘‘A Quantum Theory of the Scattering of X-rays by Light Elements, Physical
Re6iew 21 (1923), 483–502. For a full account, see Roger H. Stuewer, The Compton Effect
:
Turning Point in Physics (New York: Science History Publications, 1975).

Vol. 4 (2002) Raman and the Raman Effect 417
3 Robert W. Wood, ‘‘Wavelength Shifts in Scattered Light,’’ Nature 122 (1928), 349.
4 For accounts of Raman’s life and work, see Indian Scientists
:
Biographical Sketches with an
Account of their Researches,Disco6eries and In6entions (Madras: G. A. Natesan and Co., 1929),
pp. 183–246; P. Krishnamurti, Sir C.V.Raman
:
A Short Biographical Sketch (Bangalore: The
Bangalore Press, 1938); Jagdish Mehra, ‘‘Chandrasekhara Venkata Raman,’’ in Charles Coulston
Gillispie, ed., Dictionary of Scientific Biography, Vol. XI (New York: Charles Scribner’s Sons,
1975), pp. 264–267; G. H. Keswani, Raman and His Effect (New Delhi: National Book Trust
India, 1980); P. R. Pisharoty, C.V.Raman (New Delhi: Publications Division, 1982); S. N. Sen,
Prof.C.V.Raman
:
Scientific Work at Calcutta (Calcutta: Indian Association for the Cultivation
of Science, 1988); G. Venkataraman, Journey Into Light
:
Life and Science of C.V.Raman (New
Delhi: Indian Academy of Sciences, 1988); A. Jayaraman, C.V.Raman
:
A Memoir (New Delhi:
Affiliated East-West Private Ltd., 1989); and G. Venkataraman, Raman and His Effect (Hydera-
bad: University Press (India) Ltd., 1995.
5 S. Ramaseshan, ‘‘C. V. Raman Memorial Lecture,’’ Indian Institute of Science, Bangalore, March
3, 1978.
6 C. V. Raman, in Books That Ha6e Influenced Me
:
A Symposium (Madras: G. A. Natesan & Co.,
1947), pp. 21–29.
7 C. V. Raman, The Physiology of Vision (Bangalore: Indian Academy of Sciences, 1968).
8 C. V. Raman, ‘‘Unsymmetrical Diffraction Bands due to a Rectangular Aperture,’’ Philosophical
Magazine 12 (1906), 494–498.
9 See C. V. Raman’s comments in his paper, ‘‘Remarks on a Paper by J. S. Stokes on ‘Some
Curious Phenomena Observed in Connection with Meld’s Experiment’,’’ Physical Re6iew 32
(1911), 307–308.
10 Quoted in Pisharoty, Raman (ref. 4), p. 10.
11 C. V. Raman, ‘‘Convocation Speech delivered at Coimbatore,’’ February 28, 1953.
12 Ibid.
13 A. Mookerjee to Viceroy of India, June 29, 1912, Churchill College Archives, University of
Cambridge.
14 Venkataraman, Journey Into Light (ref. 4), p. 38.
15 V. R. Krishnan, ‘‘Lokasundari Raman,’’ Femina (May 22, 1978).
16 Minutes of the Syndicate, Calcutta University, May 11, 1917, pp. 810 – 811.
17 J. C. Bose to D. P. Sarbadhikari, August 30, 1917 (private copy).
18 G. Chattopadhyay, ‘‘The Other Side of Genius,’’ The Illustrated Weekly of India (September 24,
1989), 44–47.
19 M. N. Saha to P. K. Kichlu, August 15, 1927, Nehru Memorial Library, New Delhi.
20 M. N. Saha and B. N. Srivastava, A Treatise of Heat (Allahabad: The Indian Press, 1965), p. viii.
21 J. C. Chaudhuri, Indian Fellows of the Royal Society and Others (Calcutta: Academic Publishers,
1992), pp. 58–61.
22 A Century (Calcutta: Indian Association for the Cultivation of Science, 1976), p. 227.
23 Secretary of the Asiatic Society of Bengal to C. V. Raman, December 4 and 11, 1922.
24 C. V. Raman Nomination Certificate, November 1921, Royal Society of London Archives.
25 Chattopadhyay, ‘‘Other Side of Genius’’ (ref. 18); Amrita Bazar Patrika (June 21, 1934).
26 Chattopadhyay, ‘‘Other Side of Genius’’ (ref. 18); S. Chatterjee, ‘‘Meghnad Saha and C. V.
Raman: Fact and Fiction,’’ Indian Physical Society
:
Diamond Jubilee Number (Indian Physical
Society, 1995), pp. 43–47.
27 R. S. Krishnan, ‘‘Prof. Sir C. V. Raman,’’ Journal of Scientific and Industrial Research 30 (1971),
2–7.
28 Sen, Raman (ref. 4), pp. 136 – 137.
29 Krishnamurti, Raman (ref. 4), pp. 13 – 16.
30 N. H. Fletcher, ‘‘The Non-linear Physics of Musical Instruments,’’ Reports of Progress in Physics
62 (1999), 723–764.
31 A. Hirschberg, J. Kergomar and G. Weinreich, ed., Mechanics of Musical Instruments (Wien:
Springer-Verlag, 1995), p. 227; N. H. Fletcher and Thomas D. Rossing, The Physics of Musical
Instruments (New York: Springer-Verlag, 1998), p. 329.

R. Singh Phys. perspect.418
32 C. V. Raman, ‘‘On the Mechanical Theory of the Vibrations of Bowed Strings and of Musical
Instruments of the Violin Family, with Experimental Verification of the Results,’’ Part 1, Bulletin
of the Indian Association for the Culti6ation of Science 15 (1918), 1–158.
33 Editor, Nature 90 (1912), 367; ibid.93 (1914), 622.
34 Sen, Raman (ref. 4), p. 137.
35 Indian Association for the Cultivation of Science, Annual Report (1926), p. 268.
36 C. V. Raman, ‘‘Musikinstrumente und ihre Kla¨ nge,’’ in Hans Geiger and Karl Scheel, ed.,
Handbuch der Physik, Band 8 (Berlin: Springer, 1927), pp. 354–427.
37 Ibid., pp. 151–295.
38 Editor, ‘‘Origin of the Society,’’ The Journal of the Astronomical Society of India 1(1910 – 1911),
1–2; hereafter JASI.
39 J. J. Meikle, Editor, ‘‘Report of the Meeting of the Society, March 1912,’’ ibid.2(1911 – 1912),
144–146; C. T. Letton, Editor, ‘‘Report … , November 5, 1912,’’ ibid.3(1911– 1912), 2;
‘‘Report … , February 25, 1913,’’ ibid.3(1912– 1913), 121; ‘‘Report … , October 1913,’’ ibid.4
(1913–1914), 27.
40 C. V. Raman, ‘‘Astronomical Optics,’’ JASI 2(1911 – 1912), 224 – 229; ‘‘The Diffraction of Light
and its Relation to the Performance of the Telescope,’’ ibid., 195–203; ‘‘Spectroscopic Notes,’’
ibid., 3(1911–1912), 49–52; ‘‘Observations of the Gegenschein,’’ ibid., 4(1913–1914), 102–103;
‘‘Saturn in a Small Telescope,’’ ibid., 4(1913–1914), 154–155; ‘‘Saturn and its System,’’ ibid., 5
(1913–1916), 149–150.
41 C. T. Letton, Editor, ‘‘Report of the Meeting of the Society, March 25, 1913,’’ JASI 3
(1912–1913), 145; ‘‘Report … , June 24, 1913,’’ ibid., p. 227; J. Mitchell, ‘‘Jupiter, the Giant
Planet,’’ ibid.5(1913–1916), 136.
42 Council Members, JASI 10 (1919 – 1920), 2; C. V. Raman, ‘‘On the Diffraction Phenomena
Observed in the Testing of Optical Surfaces [Abstract]’’, ibid.7(1916–1917), 30.
43 C. V. Raman, ‘‘What would I do if I lived my Life Again?’’ The Illustrated Weekly of India (April
23, 1939), 19.
44 Keswani, Raman (ref. 4), pp. 145 – 147.
45 C. V. Raman, Molecular Diffraction of Light (Calcutta: Calcutta University Press, 1922).
46 A Century (ref. 22), p. 241.
47 Rajinder Singh and Falk Riess, ‘‘Bidhu Bhushan Ray and His Contacts to Western Scientists,’’
Science and Culture 66 (2000), 177–181.
48 There is some disagreement here with the list of visitors to the Bohr Institute between 1920 and
1930 given in Peter Robertson, The Early Years
:
The Niels Bohr Institute
1921
–
1930
(Copen-
hagen: Akademisk Forlag, 1979), pp. 156–159, on p. 158. Robertson shows Ray as spending the
period October 1924 to September 1925 at the Bohr Institute, while Ray wrote to Bohr from
Berlin on March 6, 1926, thanking Bohr for his hospitality over the past year and a half. I have
assumed that Ray’s letter gives his stay with Bohr correctly.
49 C. V. Raman, ‘‘Einstein’s Aberration Experiment,’’ Nature 109 (1922), 477 – 478; ‘‘On Einstein’s
Aberration Experiment,’’ Astrophysical Journal 56 (1922), 29–33.
50 Albert Einstein, ‘‘U
8
ber ein den Elementarprozess der Lichtemission betreffendes Experiment,’’
Preussische Akademie der Wissenschaften,Sitzungsberichte 51 (1921), 882–883.
51 For a full discussion, see Martin J. Klein, ‘‘The First Phase of the Bohr-Einstein Dialogue,’’
Historical Studies in the Physical Sciences 2(1970), 1–39, esp. 8–13; Stuewer, Compton Effect (ref.
2), pp. 218–219,
52 Raman, ‘‘Einstein’s Aberration Experiment’’ (ref. 49, both papers).
53 C. V. Raman, ‘‘Diffraction by Molecular Clusters and the Quantum Structure of Light,’’ Nature
109 (1922), 444–445; reprinted in The Scientific Papers of Sir C.V.Raman
:
The Scattering of
Light (Bangalore: The Indian Academy of Sciences, 1978), pp. 149–151.
54 Raman, Molecular Diffraction of Light (ref. 45), pp. 98 – 101.
55 K. Milton, The Scattering of Light and Other Electromagnetic Radiation (London: Academic Press,
1969), p. 27.
56 Lord Rayleigh, ‘‘On the Transmission of Light through an Atmosphere containing Small Particles
in Suspension, and on the Origin of the Blue of the Sky,’’ Philosophical Magazine 47 (1899),
375–384; reprinted in Scientific Papers, Vol. IV.
1892
–
1901
(Cambridge: Cambridge University
Press, 1903), pp. 397–405.

Vol. 4 (2002) Raman and the Raman Effect 419
57 Lord Rayleigh, ‘‘Colours of the Sea and Sky,’’ Nature 83 (1910), 48ff; reprinted in Scientific Papers,
Vol. V.
1902
–
1910
(Cambridge: Cambridge University Press, 1912), pp. 540–546.
58 C. V. Raman, ‘‘On the Molecular Scattering of Light in Water and the Colour of the Sea,’’
Proceedings of the Royal Society of London [A] 101 (1922), 64–80; reprinted in Scientific Papers
(ref. 53), pp. 15–31.
59 C. V. Raman, ‘‘Anisotropy of Molecules,’’ Nature 109 (1922), 75 –76; reprinted in Scientific Papers
(ref. 53), pp. 34–35.
60 C. V. Raman and K. R. Ramanathan, ‘‘On the Molecular Scattering of Light in Dense Vapours
and Gases,’’ Phil.Mag.45 (1923), 113–138; reprinted in Scientific Papers (ref. 53), pp. 163–178.
61 C. V. Raman, ‘‘Molecular Aelotropy in Liquids,’’ Nature 110 (1922), 11; reprinted in Scientific
Papers (ref. 53), pp. 152–154. C. V. Raman and K. S. Rao, ‘‘On the Molecular Scattering and
Extinction of Light in Liquids and the Determination of the Avogadro Constant,’’ Phil.Mag.
45
(1923), 625–640; reprinted in Scientific Papers (ref. 53), pp. 179–194.
62 K. R. Ranamathan, ‘‘Electromagnetic Theory of the Scattering of Light in Fluids,’’ Proceedings
of the Indian Association for the Culti6ation of Science 8(1922–1923), 1–22; hereafter Proc.IACS.
63 K. R. Ranamathan, ‘‘Electromagnetic Theory of the Scattering of Light in Fluids. Paper B,’’ ibid.,
pp. 181–198.
64 K. S. Krishnan, ‘‘On the Molecular Scattering of Light in Liquids,’’ Phil.Mag.50 (1925), 697 –715.
65 C. V. Raman, ‘‘The Raman Effect: Investigations on Molecular Structure by Light Scattering,’’
Transactions of the Faraday Society 25 (1929), 781–792.
66 Quoted in Arthur Holly Compton, ‘‘Personal Reminiscences,’’ in Marjorie Johnston, ed., The
Cosmos of Arthur Holly Compton (New York: Knopf, 1967), p. 37.
67 Stuewer, Compton Effect (ref. 2), p. 268; A. Sur, ‘‘Aesthetics, Authority, and Control in an Indian
Laboratory: The Raman-Born Controversy on Lattice Dynamics,’’ Isis 90 (1999), 25–49.
68 William Duane, ‘‘On Secondary and Tertiary Radiation,’’ British Association for the Ad6ancement
of Science Report (London: British Association, 1925), p. 363.
69 Stuewer, Compton Effect (ref. 2), pp. 272 – 273.
70 Arthur H. Compton, ‘‘The Quantum Theory of the Scattering of X-Rays,’’ British Association
Report (ref. 68), p. 363.
71 J. A. Gray, ‘‘Scattering of X- and Gamma-rays and the Production of Tertiary X-rays,’’ ibid.
72 Anonymous, ‘‘The Scattering of X-Rays,’’ Nature 114 (1924), 627 – 628.
73 Compton, ‘‘Quantum Theory’’ (ref. 2), p. 401.
74 Anonymous, ‘‘Scattering’’ (ref. 72).
75 C. V. Raman to Niels Bohr, March 13, 1932, Niels Bohr Archive, Copenhagen.
76 C. V. Raman, ‘‘Thermodynamics, Wave-theory, and the Compton Effect,’’ Nature 120 (1927),
950–951; reprinted in Scientific Papers (ref. 53), pp. 447–449.
77 Ibid.
78 C. V. Raman, ‘‘A Classical Derivation of the Compton Effect,’’ Indian Journal of Physics 3(1928),
357–369; reprinted in Scientific Papers (ref. 53), pp. 450–462.
79 C. V. Raman and C. M. Sogani, ‘‘A Critical-Absorption Photometer for the Study of the Compton
Effect,’’ Proc.Roy.Soc.London [A] 119 (1928), 526–530; reprinted in Scientific Papers (ref. 53),
pp. 439–446. See also ‘‘X-ray Diffraction in Liquids,’’ Nature 120 (1927), 514; reprinted in
Scientific Papers, pp. 436–437, and C. V. Raman ‘‘Thermal Degeneration of the X-ray Haloes in
Liquids,’’ ibid., p. 770; reprinted in Scientific Papers, p. 438.
80 Quoted Compton, ‘‘Personal Reminiscences,’’ in Johnston, Cosmos (ref. 66), p. 37.
81 Betty McCloskey Compton interview by Charles Weiner, April 11, 1968, Niels Bohr Library,
American Institute of Physics, College Park, Maryland, p. 61.
82 Ibid., p. 85.
83 C. V. Raman, ‘‘A New Radiation,’’ Indian J.Phys.2(1927 – 1928), 388 – 398; reprinted in Scientific
Papers (ref. 53), pp. 467–479, on p. 471.
84 C. G. Darwin, ‘‘A Quantum Theory of Optical Dispersion,’’ Nature 110 (1922), 841 – 842.
85 A. Smekal, ‘‘Zur Quantentheorie der Dispersion,’’ Die Naturwissenschaften 43 (1923), 873 – 875.
86 H. A. Kramers, ‘‘The Law of Dispersion and Bohr’s Theory of Spectra,’’ Nature 113 (1924),
673–674; ‘‘Quantum Theory of Dispersion,’’ ibid.114 (1924), 310–311; H.A. Kramers and W.
Heisenberg, ‘‘U
8
ber die Streuung von Strahlund durch Atome,’’ Zeitschrift fu¨r Physik 31 (1925),
681–708.

R. Singh Phys. perspect.420
87 For a full discussion, see Max Jammer, The Conceptual De6elopment of Quantum Mechanics,
Second Edition (New York: Tomash Publishers and American Institute of Physics, 1989), pp.
208–227. See also Hans A. Bethe, ‘‘Quantum Theory,’’ Re6iews of Modern Physics 71 (1999), 1–5.
88 G. S. Landsberg and L. I. Mandelstam, ‘‘Eine neue Erscheinung bei der Lichtzerstreuung in
Krystallen, Naturw.16 (1928), 557–558; ‘‘U
8
ber die Lichtzerstreuung in Kristallen,’’ Zeit.f.Phys.
50 (1928), 769–780; ‘‘Sur des faits nouveau relatifs a` la diffusion de la lumie`re dans les cristaux,’’
Comptes rendus 186 (1928), 109–111.
89 Raman, ‘‘New Radiation’’ (ref. 83).
90 Krishnan, ‘‘Molecular Scattering’’ (ref. 64).
91 Raman, ‘‘New Radiation’’ (ref. 83).
92 B. Chase, ‘‘A New Generation of Raman Instrumentation,’’ Applied Spectroscopy 48 (1994),
14–19.
93 Landsberg and Mandelstam, ‘‘neue Erscheinung’’; ‘‘Lichtzerstreuung’’ (ref. 87).
94 Clemens Scha¨ fer and Frank Matossi, ‘‘Der Ramaneffekt,’’ in A. Eucken, ed., Fortschritte der
Chemie,Physik und Physikalische Chemie 20 (Berlin: Gebru¨ der Borbtreger, 1929), p. 22.
95 Raman, ‘‘New Radiation’’ (ref. 83).
96 C. V. Raman and K. S. Krishnan, ‘‘A New Type of Secondary Radiation,’’ Nature 121 (1928),
501–502; reprinted in Scientific Papers (ref. 53), pp. 463–464.
97 Ibid.; C. V. Raman, ‘‘A Change of Wave-length in Light Scattering,’’ Nature 121 (1928), 619;
reprinted in Scientific Papers (ref. 53), pp. 465–466.
98 Landsberg and Mandelstam, ‘‘neue Erscheinung’’(ref. 88).
99 Raman, ‘‘New Radiation’’(ref. 83).
100 R. S. Krishnan and R. K. Shankar, ‘‘Raman Effect: History of the Discovery,’’ Journal of Raman
Spectroscopy 10 (1981), 1–8.
101 Y. Rocard, ‘‘Les Nouvelles radiations diffuse´es,’’ Comptes rendus 186 (1928), 1107 – 1108.
102 G. Joos to A. Sommerfeld, May 14, 1928, Deutsches Museum Archive, Munich.
103 A. Sommerfeld to G. Joos, June 9, 1928, Deutsches Museum Archive, Munich.
104 P. Pringsheim, ‘‘Der Ramaneffekt, ein neuer von C. V. Raman entdeckter Strahlungseffekt,’’
Naturw.31 (1928), 597–601; P. Pringsheim and B. Rosen, ‘‘U
8
ber den Ramaneffekt,’’ Zeit.f.Phys.
50 (1928), 741–755.
105 P. Pringsheim, ‘‘Ramanspektra,’’ in Hans Geiger, ed., Handbuch der Physik, Band 21 (Berlin:
Springer, 1929).
106 G. Joos, ‘‘Ramaneffekt,’’ in W. Wien and F. Harms, ed., Handbuch der Experimentalphysik, Band
22 (Leipzig: Akademische Verlagsgesellschaft, 1929), pp. 413–421.
107 Scha¨ fer and Matossi, ‘‘Ramaneffekt,’’ (ref. 94).
108 K. W. F. Kohlrausch, Der Smekal -Raman -Effekt (Berlin: Springer, 1931).
109 J. H. Hibben, ‘‘A Statistical Analysis of Trends in Research in the Raman Effect,’’ Proc.IACS 8
(1938), 294–300.
110 Nobel Foundation, Nobel Lectures Physics
1922
–
1941
(Amsterdam: Elsevier, 1965), p. 261.
111 R. G. W. Brown and E. R. Pike, ‘‘A History of Optical and Optoelectronic Physics in the
Twentieth Century,’’ in Laurie M. Brown, Abraham Pais, and Sir Brian Pippard, ed., Twentieth
Century Physics, Vol. 3 (Bristol and Philadelphia: Institute of Physics Publishing and New York:
American Institute of Physics Press, 1995), pp. 1385–1504, esp. pp. 1404–1406; Keswani, Raman
(ref. 4); I.L. Fabelinskii, ‘‘The Discovery of Combinational Scattering of Light (the Raman
Effect),’’ Physics-Uspekhi 21 (1978), 780 – 797; ‘‘Seventy Years of Combination (Raman) Scatter-
ing,’’ ibid.41 (1998), 1129–1247.
112 Rajinder Singh and Falk Riess, ‘‘In 1930 the Nobel Prize for Physics – a Close Decision?’’ Notes
and Records of the Royal Society of London 55 (2001), 267–283.
Department of Higher Education and History of Science
Faculty of Physics
University of Oldenburg
P.O. Box 2503
D-26111 Oldenburg, Germany
e-mail: rajinder.singh@mail.uni-oldenburg.de