B. C. Fawcett's research while affiliated with University of California and other places

Publications (111)

Article
Emission lines which result from transitions betwen principal quantum numbers 2 and 3 in S X to XIV P X to XII, Cl XI to XIV and Ar XII and XIII are classified. The spectra were emitted from the plasma produced in a theta-pinch into which a small quantity of hydrogen sulphide, phosphine, chlorine or argon was added. Wavelength measurements in sulph...
Article
Energy levels and oscillator strengths are calculated for the 3s23pn -3s23pn-13d transition arrays of Fe X and Fe XI. The Slater radial integrals for these computations are adjusted so as to become consistent with established energy levels. Pertinent configuration interactions are included and the interaction integrals are reduced by up to 35% from...
Article
Spectroscopic observations of a theta-pinch plasma are analysed, resulting in the classification of nearly 200 spectral lines of ArV to ArX. The ArIX data are of particular interest as the observed lines mainly belong to the 2p53d-2p54f, 5f, 6f, and 2p53p-2p54d, 5d, 4s, 5s and 2p53s-2p54p transition arrays, for which no information previously exist...
Article
The 3s2 3p6 3d2-3s2 3p5 3d3 and 3s2 3p6 3d2-3s2 3p5 3d4p, 4f, 5f transition arrays of Co VIII are analysed and energy levels established. A few of the strongest Ni IX and Cu X lines from the former array are also identified. Large irregularities along the isoelectronic sequence are found. Theoretical calculations of atomic energy levels and oscilla...
Article
This review of recent contributions to the classification of the spectra of highly ionised atoms emphasises how major research projects have influenced progress. These projects include experiments on board orbiting space satellites and SKYLAB, those of fusion research (notably involving TOKAMAK devices), studies with giant pulse laser-produced-plas...
Article
Weighted oscillator strengths are computed for ions in the isoelectronic sequence between A1 IV and Ar IX. They were computed with a programsuite which uses the Hartree-Fock-Relativistic and Blume-Watson methods and takes into account configuration interaction. Slater parameters were optimised based on empirical data. Values of energy levels of Ar...
Article
The spectra of a laser-produce-plasma and a theta-pinch plasma were recorded with a grazing incidence spectrograph. Comparison of these spectra enabled the tabulation of a comprehensive list of wavelengths and identifications of phosphorus VI to XIII emission lines between 22 and 92 Å. This incorporates a review of H. A. Robinson's unpublished work...
Article
Oscillator strengths, wavelengths and energy levels of Fe XV are calculated with a Hartree-Fock-Relativistic (HFR) computer program. Optimisation procedures are applied to establish agreement between computed and observational data. Multiconfiguration-Dirac-Fock (MCDF) and HFR computations are compared for ions in the Mg I isoelectronic sequence. T...
Article
A detailed investigation of energy levels and radiative transition probabilities is presented for the n = 4, Δn = 0 transitions of the ions Rb VIII to Xe XXV along the zinc isoelectronic sequence. The Relativistic Hartree-Fock method is applied for the calculations combined with Slater parameter optimization procedures. Comparisons with multiconfig...
Article
A spectroscopic analysis of light emitted in the 2000-6000 Å wavelength range by Ar7+ and Ar6+ ions produced in Ar8+ -He and Ar8+ -H2 collisions at 120 keV is performed. Well resolved fine structure components of 5s-5p and 5p-5d transitions in Ar VIII following single electron capture are precisely measured. Predominant lines due to double electron...
Article
Lines of scandium, titanium and vanadium have been observed at wavelengths below 31 Å. These and some argon lines are classified as transitions in the Ne 1 and F 1 isolectronic sequences involving a principal quantum number change of 2-3 or 2-4.
Article
Plasmas produced by focusing a 400 MW ruby laser beam onto surfaces of C, Ti, Mn, Fe, Ni, Cu and Zn, and into argon gas, have been observed in the extreme ultra-violet region. Line and continuum radiation have been recorded down to 25 Å, including new spectra of Fe XV and Fe XVI and Ni XVII and Ni XVIII. The value of such plasmas for line classific...
Article
Spectral lines of T1 VII to XII and isoelectronic transitions of wavelengths between 250 and 600 Å are classified Identifications of Fe XIV solar lines are confirmed, including the visible coronal line at 5302 86 Å The ions were excited in a plasma produced by a 500 MW laser beam focused onto metal targets. The target of the pure metal was situated...
Article
Plasmas generated by focusing Q-spoiled ruby lasers onto solid targets are used as spectroscopic sources for the study of far vacuum ultra-violet emission spectra of ions of astrophysical interest. New, inner-shell transitions of fluorine-, oxygen- and nitrogen-like ions are classified in S X, K XI, XII, XIII, Ca XII, XIII, XIV, Sc XIII and Ti XIV...
Article
The electromagnetic emission from plasmas produced by irradiating solid targets with focused light from Q-spoiled ruby lasers is recorded with grazing- and normal-incidence spectrographs as a function of plasma radius and of distance from the target The plasma density and temperature are thereby evaluated. Observed linewidths of the order of 103 cm...
Article
Many of the stronger members of the group of solar emission lines between 167 Å and 220 Å have been classified as transitions of the type 3pn-3pn-13d in Fe IX to Fe XIV and 3p63d-3p53d2 in Fe VIII. The method is based upon following the isoelectronic sequences from nickel down, where possible, to known spectra. The sources used include Zeta and vac...
Article
The use of vacuum sparks and laser-produced plasmas has enabled many of the stronger transitions from these ions to be classified. New lines of Fe XII and XIII complete the classification of the intense members of the solar emission line group at 167 Å to 220 Å.
Article
Term values and oscillator strengths in highly ionized ions of the iron period are calculated via the Slater theory of atomic structure and are used to identify laboratory spectra of 3s2 3pn-3s2 3pn-1 4s, 5s, 4d, 5d transitions in the argon, chlorine and sulphur isoelectronic sequences. New classifications are made in argon, scandium, titanium, van...
Article
This paper classifies 120 emission lines resulting from 2s22pn-2s2pn+1 transitions in elements in the period between calcium and iron isoelectronic with Fe XVIII to Fe XXI. From the data presented energy levels of terms arising from the ground configuration can be calculated which can be of use in the prediction of the wavelengths of forbidden line...
Article
Nearly 170 emission lines of Fe X to XV, Mn X to XIV, Cr X to XII and VIX to X, which result from 3s2 3pN-3s 3pN+1 and 3pn-3pn-1 3d transitions are classified. Of particular interest are the extensions to the analysis of the spectra of Fe XII and Fe XIII. The analysis of these transitions is complete apart from lines which are probably absent from...
Article
The spectra of laser-produced plasmas emitted from targets of pure sulphur and phosphorus in the wavelength region between 20 AA and 300 AA were analysed. As a result over fifty newly classified lines of sulphur X to XIV and sixteen of phosphorus XI to XII are reported and a further 150 previous identifications in phosphorus VI to XIII are confirme...
Article
230 newly classified spectral lines emitted from higly ionized elements and belonging to the sodium, magnesium, aluminium, silicon, phosphorus, sulphur and chlorine isoelectronic sequences are reported as a result of observations of laser-produced plasmas formed from elements in the period between chlorine and iron. The transitions studied occur be...
Article
180 spectral lines at wavelengths between 240 and 750 AA are classified. They arise from transitions from singly and doubly excited levels in Na VII-IX, Mg VI-X, Al VII-XI, Si VII-XII, P X-XIII, S XI-XIV, Cl XII-XV, K XIII and Ca XIV, In addition 59 emission lines of chlorine XII-XV are classified in the region between 17 aa and 40 aa. The spectra...
Article
This paper reports the classification of spectral lines of chlorine IX to XIV and of argon X to XV emitted from the plasma formed in a theta pinch. The spectra were recorded photographically using a fast shutter to isolate the period of interest. Additional wavelengths of isoelectronic lines in silicon, phosphorus and sulphur are also presented, th...
Article
Emission lines are classified belonging to 2s22pn-2s2pn+1 transition arrays in the ions Ti XVII, V XVII to XX, Mn XVIII, MN XIX, Fe XIX and Fe XX. The source of these ions is the plasma produced at metallic surfaces irradiated with a neodymium laser beam with a focused power density in the range of 1012 to 1013 W cm-2 at the target surface. The dat...
Article
Gives lithium, beryllium, boron and carbon-like spectral line classifications of F III to VII, Na VI, Na X, Mg VII, Mg X, Al VIII, X, XI, and Si IX and XII which are based on observations of laser produced plasmas. The identifications are mainly of transitions between levels of principle quantum number n=3 and 4 but also include 2s2p3-2p4 transitio...
Article
3pn-3pn-14s,4d and 3pn3d-3pn4p,4f transitions of Fe IX to XVI and Mn VIII to XV are classified through comparison of observed spectra with spectra computed using atomic self consistent field calculations. The required quality of observations was achieved by recording data during the short period when a theta-pinch emitted spectra from the ionizatio...
Article
The far ultraviolet spectra of the highly ionized solar-abundant element nickel is analysed on the basis of new observations of laser produced plasmas. The transitions involved are mainly between principal quantum numbers 3 and 4 and their spectra are observed and classified in isoelectronic elements in the period between nickel and scandium with t...
Article
The 3s2 3pn-3s 3pn+1 and 3pn-3pn-1 3d transitions in Ni XI to XVII and Co X to XVII are classified as a result of the analysis of the spectra emitted from a theta-pinch plasma containing small percentages of nickel or cobalt carbonyl. The nickel lines account for a number of lines in the solar spectrum between 140 AA and 300 AA. The observations ch...
Article
The plasma produced by focusing the output beam of a 1 GW CO2 laser on to solid targets was observed with a grazing incidence spectrograph. Measurements of electron temperature, density and ion velocity are reported.
Article
Full-text available
Satellite lines are identified in the X-ray spectrum of foil-excited fast silicon ions. These lines result from transitions from levels of principal quantum number n: up to n=6 in He-like Si XIII, up to n=5 in Li-like Si XII, and up to n=3 in Si XI, Si X, Si IX and Si VIII. The identifications are made with the aid of theoretical 'Hartree-XR' atomi...
Article
Emission lines of krypton IV and V belonging to the 4s24pq-4s24pq-14d and 4s24pq-4s4pq+1 transition arrays are classified with the aid of a theoretical model developed for analogous Fe XII and Fe XIII transitions in a different atomic shell. Xenon VI lines are also identified. The observational material consisted of archived Zeta spectrograms.
Article
Foil excitation of fast ion beams has been used to produce few-electron ions of magnesium and aluminium. The emission spectra have been analysed with a 10 cm curved crystal X-ray spectrometer. The spectra show series of transitions in H- and He-like ions and numerous satellite lines. By comparison with Hartree-XR calculations, these lines are seen...
Article
New observations of spectra resulting from transitions between levels of principal quantum numbers 3 and 4 are reported. The spectra were emitted from plasmas produced through focusing the output of a 4 GW neodymium-glass laser on to plane solid targets. Observations are of spectra of ions in the lithium I isoelectronic sequence between Mg X and Ti...
Article
Full-text available
Knowledge of accurate oscillator strengths in neutral oxygen is of crucial importance in astrophysics. The accurate determination of the solar abundance of O I, which remains the primary source for the entry in cosmic abundance tables, requires the use of E1 transitions appearing in the solar photospheric spectrum. A new accurate scale of oscillato...
Article
Improved atomic data for Ti VI and Fe X are calculated with atomic-structure codes which incorporate Slater parameter optimization. These semiempirical calculations rely on newly reported energy level identifications and measurements in Ti VI, on the basis of which a computational model was established for Ti VI and then applied to compute improved...
Article
Weighted oscillator strengths are tabulated for 2745 spectral lines in Yb II. They belong to transitions between the 4f146s, 4f147s, 4f148s, 4f145d, 4f146d, 4f147d, 4f136s6p, and 4f135d6p even configurations and the 4f146p, 4f147p, 4f136s2, 4f135d6s, and 4f135d2 odd configurations in Yb II. The calculations included configuration interaction betwee...
Article
Ar7 + ion beam collisions at 105 kev on He and molecular hydrogen targets are studied by photon spectroscopy. New transitions of the Ar6+ and Ar5+ spectra due to single and double electron captures are observed and interpreted through ab initio calculations.
Article
This presentation considers how the interaction between physical conditions in plasmas and atomic-structure properties affects the role played by highly-charged ions. It is emphasised that reliable and accurate atomic data are required to determine plasma conditions from the analysis of spectral line intensities. Atomic-structure problems which lim...
Article
Collision strengths and oscillator strengths are calculated for Fe IX. The three configurations 3s²3p⁶, 3s²3p⁵3d, and 3s²3p⁵4s were included in the computations. The data can be applied to the analysis of spectral lines in the solar spectrum and laboratory sources. The collision calculations were executed with the DISTORTED WAVE collision...
Chapter
It is important to investigate whether non—relativistic errors in calculated oscillator strengths and related atomic data are large enough to obscure corrections applied in relativistic calculations. The magnitude such errors is however difficult to estimate. This is just one reason why the accuracy of the atomic data needs careful scrutiny. Applic...
Article
Weighted oscillator strengths are tabulated for 6185 spectral lines in Ce II, some of which are found in the solar spectrum. They belong to transitions between the 4f5d2, 4f5d6s, 4f6s2, 4f26p, and 4f3 odd configurations and the 4f26s, 4f25d, 4f5d6p, 5d3, 4f6s6p, and 5d26s even configurations. The values were calculated by a method in which Slater p...
Article
Lande g values are calculated for the astrophysically abundant ion Fe II. They are compared with published measured values in order to indicate possible errors that can affect calculated oscillator strengths and eigenvectors. Both the computations of Lande g values and previous oscillator strengths calculations were carried out at the Rutherford Ap...
Article
Details of a new computational method for calculating collision strengths are presented through an application to Fe XIII. The method, which enables the computation of collision strengths for complex ions, is adapted from long-established optimization techniques previously used for the calculation of atomic energy levels and oscillator strengths. T...
Article
Full-text available
Atomic data including energy levels, gf-values, and wavelengths are given for the Fe XIX transitions that give rise to lines in solar-flare and active-region X-ray spectra. Collision strengths and theoretical intensity ratios are presented for lines which occur in the 13.2-14.3-A range. Observed spectra are found to be consistent with those derived...
Article
The primary objective of the calculations presented here is to provide reliable oscillator strengths for the analysis of solar spectra of Fe VIII and Ni X belonging to the 3s²3p⁶3d-3s²3p⁵3d² transition array. To achieve this it was necessary to study interacting configurations which cross the 3s²3p⁵3d² configuration for ions in the perio...
Article
Calculated weighted oscillator strengths are tabulated for spectral lines of Fe III, Fe IV, Fe V, and Fe VI. The lines belong to transition arrays 3d⁶-3d⁵4p and 3d⁵4s-3d⁵4p in Fe III, 3d⁵-3d⁴4p and 3d⁴4s-3d⁴4p in Fe IV, 3d⁴-3d³4p and 3d³4s-3d³4p in Fe V, and 3d³-3d²4p and 3d²4s-3d²4p in Fe VI. For the calculations, Slater p...
Article
In a study of Si XIn=3 ton=4 transition arrays highly resolved beam-foil spectra in the spectral region 13–16 nm were compared with simulated spectra computed with a Hartree-Fock-Relativistic program package. The computational method involved the scaling of Slater parameters. The general structure of measured and simulated spectra is very similar,...
Article
Weighted oscillator strengths for spectral lines of Fe II previously identified in the solar spectrum are tabulated for wavelengths between 1361 and 6483 Å. Data are also included for lines emitted from the slow nova RR Tel between 2000 and 3213 Å.
Article
Weighted oscillator strengths for Fe I are calculated for the 3d64s2-3d64s4p, 3d64s2-3d74p, 3d74s-3d74p, and 3d74s-3d64s4p transition arrays. A selection of normalized values is listed and compared with experimental values compiled in the literature. Cancellation factors are also tabulated. The accuracy of the data is discussed and the effects of c...
Article
Weighted oscillator strengths of allowed transitions for the ions C I, N II, and O III are computed with a Hartree-Fock-Relativistic program package. The overlap of configurations of different principal quantum numbers is taken into account through the inclusion of interacting configurations up to n = 5. Slater parameter optimization procedures are...
Article
Wavelengths and weighted oscillator strengths are tabulated for C-like ions in the isoelectronic sequence between F IV and Ni XXIII. Data are listed for transitions between the 2s22p2 even and the 2s2p3, 2s22p3s, 2s22p3d, and 2s2p23p odd configurations, and between the 2s2p3 odd and the 2p4, 2s2p23s, and 2s2p23d even configurations. The computation...
Article
These tables contain weighted oscillator strengths for over 2300 Fe II lines belonging to the 3d7 − 3d64p, 3d64s − 3d64p, 3d64s − 3d54s4p, 3d7 − 3d54s4p, 3d54s2 − 3d64p, 3d54s2 − 3d54s4p, 3d64p − 3d64d, 3d64p − 3d65s, 3d7 − 3d65p, 3d64s − 3d65p, and 3d64d − 3d64f transition arrays. Computed wavelengths and wavelengths derived from established energ...
Article
A comprehensive wavelength list of classified spectral emission lines of sulphur VII to XIV between 22 and 72 Å is tabulated along with computed weighted oscillator strengths. Energy levels derived from the data are also listed and compared with computed values. The sulphur spectra were emitted from a theta-pinch plasma and also from a laser-produc...
Article
A solar flare spectrum in the wavelength region between 7.8 and 10.0 Å, recorded by the Flat Crystal Spectrometer on Solar Maximum Mission during a flare on 1985 July 2, is presented. It includes several spectral emission lines not hitherto reported. Most are identifed through comparison with wavelengths either measured in laser-produced spectra or...
Article
These tabulations of atomic data for Cl-like ions complete a series of four sets covering 3s23pn−3s3pn+1 and 3s23pn−3s23pn−13d transitions in the Cl, S, P, and Si-like ions. The work firmly demonstrates the discrepancies between measured values and the most advanced ab initio computed wavelengths of complex atomic structures, the success of semiemp...
Article
These tables contain calculated wavelengths and oscillator strengths as well as measured wave-lengths for 3s23p2-3s3p3 and 3s23p2-3s23p3d transitions, and energy levels and level compositions for the 3s3p3 and 3s23p3d configurations, of ions in the Si I isoelectronic sequence between Si I and Ni XV. The computational method is the same as that rece...
Article
Wavelengths and oscillator strengths are calculated for 3s23p4-3s3p5, 3s23p4-3s23p33d, and 3s23p4-3s23p34s transitions, and energy levels for the 3s23p33d configuration, of ions in the S I isoelectronic sequence between S I and Ni XIII. Measured wavelengths are also listed for 3s23p4-3s23p33d transitions. Enhanced accuracy is obtained through the o...
Article
Wavelengths and weighted oscillator strengths are calculated for the 2s22p4-2s2p5, 2s2p5-2p6, 2s22p4-2s22p33s, and 2s22p4-2s22p33d transition arrays for O-like ions in the isoelectronic sequence from Mg V to Ni XXI. The computational method involved the optimization of Slater parameters (radial energy integrals) based on empirical data. These param...
Article
The soft (10-100 A) X-ray spectrum of an M-class solar flare was observed with a high-resolution (0.02 A) rocket-borne spectrograph on 1982 July 13. The spectrum samples an area of 600/sq arcsec on the sun, centered on or near the brightest X-ray feature of the flare. Several hundred emission lines characteristic of temperatures from about 0.5 to 7...
Article
Weighted oscillator strengths, energy levels, and wavelengths are calculated for the 2s22p5-2s2p6, 2s22p5-222p43s, and 2s22p5-2s22p43d transition arrays for F-like ions in the isoelectronic sequence from Mg IV to Ni XX and in addition for n = 3−3 and other transitions in Mg IV, Al V, and Si VI. The calculation involves the computation of ab initio...
Article
The authors re-emphasize the importance of both spin-orbit interaction and configuration-mixing effects in the calculation of wavelengths and oscillator stengths for heavy-element moderately-ionized spectra; with particular reference to Fe X resonance lines. They correct several rather misleading statements in a recent paper by R. Glass on Fe X, an...
Article
Calculated wavelengths and weighted oscillator strengths are listed for allowed n = 2−2, 2−3, and 3−3 transitions in ions belonging to the Be-like isoelectronic sequence between Be I and N IV. Additionally, selected transitions involving levels up to n = 5 are given. This extends previous tabulations for n = 2−3 transitions in ions (O V to Ni XXV)...
Article
The present state of spectroscopy related to highly ionized atoms is examined, taking into account early developments after the Second World War and prospects for the future. Applications of this area of spectroscopy are related to the study of atomic energy levels, the interpretation of astronomical spectral observations, and the diagnostics of pl...
Article
Calculated weighted oscillator strengths (O V to Ni XXV), wavelengths (Mg IX to Ni XXV), and energy levels (S XIII to Ni XXV) are listed for n = 2–3 transitions in ions belonging to the Be-like isoelectronic sequence along with available measured wavelengths (Mg IX to Ni XXV). They were computed with the aid of a Hartree-Fock-Relativistic computer...
Article
Weighted oscillator strengths, energy levels, and wavelengths are calculated for the 3s2-3s3p, 3s3p-3p2, 3s3p-3s3d, 3p2-3p3d, and 3s3d-3p3d transition arrays for Mg-like ions in the sequence from S V to Ni XVII. Their values are tabulated along with Slater radial integrals, Racah reduced radial dipole matrix elements, and level compositions. The th...
Article
Theoretical wavelengths and weighted oscillator strengths are tabulated for spectral emission lines of the ions Cl V, Ar VI, Ca VIII, Ti X, Cr XII, Fe XIV, and Ni XVI, together with available measured wavelengths. The computations are made in a theoretical framework which includes all configuration-interactions within the complex of principal quant...
Article
X-ray spectra of foil-excited fluorine and silicon ions at tandem energies have been observed with a curved-crystal spectrometer. The higher spectral resolution compared with previous beam-foil work on F has permitted the identification of satellite lines to transitions in F IX and F VIII arising from F4+-F7+ core-excited ions. In addition, the Kal...
Article
High-resolution solar X-ray spectra obtained with the Flat Crystal Spectrometer aboard the Solar Maximum Mission from two solar flares and a nonflaring active region are analyzed. The 1-22 A region was observed during the flare on 1980 August 25, while smaller spectral regions were repeatedly covered during the 1980 November 5 flare. Voigt profiles...
Article
Spectra emitted from plasmas produced through focusing the output of a 4-GW neodymium-glass laser onto plane solid targets of potassium, calcium, scandium, titanium, and vanadium were recorded with a 2-m grazing incidence spectrograph as were argon spectra emitted from a theta-pinch plasma. The analysis of the spectrograms yielded line classificati...
Article
Spectra belonging to the 3s(2)3p(n)-3s3p(n+1) transition arrays emitted from nickel ions which are of interest for the interpretation of solar spectrograms are classified along with isoelectronic spectra in cobalt ions. The analysis relied on new spectroscopic observations of a theta-pinch plasma into which nickel carbonyl was added to the filling...
Article
Spectral line classifications and wavelength measurements are presented which provide essential data for the interpretation of soft X-ray spectroscopic observations of solar flares. Ni XXV and Ni XXVI spectral lines are identified in spectra emitted from plasmas formed by focusing the output of the Rutherford Laboratory multigigawatt neodymium lase...
Article
An analysis of spectrograms of laser-produced plasmas is extended to include the strongest emission lines due to transitions between levels of principal quantum numbers n = 3 and 4 for ions in the Ne I isoelectronic sequence between K X and Fe XVII. Spectral-line classifications are supported by theoretical Hartree-XR and Slater-Condon computations...
Article
These tables list theoretical values both for weighted oscillator strengths for 2s22pn-2s2pn+1 and 2s2pn+1-2pn+2 electric dipole transitions and for 2s22pn magnetic dipole and electric quadrupole transitions. The theoretical method applied takes into account interactions between configurations of the same complex and also involves adjustment of ab...
Article
Be I-like spectra of V XX and Fe XXIII and B I-like spectra of Fe XXII are classified as a result of spectroscopic observations of the plasmas formed by focusing the output of a neodymium glass laser onto plane solid targets. Wavelength measurements published by the Lebedev Institute, Moscow, were also used, for the iron spectra. The analysis was u...
Article
A detailed analysis of the $2s^{2} 2p^{2} 3d$ configuration is presented for ions in the isoelectronic sequence from Si VIII to Fe XX. Slater parameters are adjusted to become consistent with established observational data, and then used to compute energy levels and oscillator strengths of $2s^{2}2p^{3} - 2s^{2} 2p^{2} 3d$ transitions. New line ide...
Article
Slater radial-integral parameters for the 2s(2) 2p(3) 3d configuration are adjusted by least-squares optimization so that they become consistent with observed spectra of 2s(2) 2p(4)-2s(2) 2p(3) 3d transitions in the Fe XIX isoelectronic sequence. From the adjusted parameters, energy levels and oscillator strengths are computed for this transition a...
Article
This detailed analysis of spectra due to 2s(2) 2p(2)-2s(2) 2p 3d transitions has resulted from the application of atomic energy-level calculations in which Slater parameters are adjusted so as to be consistent with established observations data. Wave lengths and energy levels are provided for elements in the isoelectronic sequence between phosphoru...
Article
Tables of wavelengths and classifications of observed emission lines due to 2s22pn−2s2pn + 1 and 2s2pn−2pn + 1 transitions are presented. The accuracy of data derived from different experimental methods is discussed. Revised and predicted wavelengths are added. Energy levels are derived from the wavelength data.
Article
Spectroscopic observations of plasmas produced when the output of a 4 GW neodymium laser was focused onto solid targets of elements in the period between copper and molybdenum have led to line classifications of spectra of higher ionized atoms from copper through bromine. Identifications include lines of ions up to the twenty-fifth stage of ionizat...
Article
Solar flare emission lines due to 2s/n/2p/k/-2s/n-1/2p/k+1/ transitions of Fe XVIII to Fe XXIII are identified in the spectral region between 66 and 140 A. The published solar flare spectra from the Goddard Space Flight Center experiment on OSO 5 were used for this analysis. Line classifications are based on data acquired from recent laboratory obs...
Article
Potassium, calcium, scandium, titanium, vanadium and chromium emission lines are classified in the same isoelectronic sequences as Fe XIX to Fe XXIII. Most of the lines identified belong to the 2pn–2pn–13d or 2s²2pk–2s 2pk+1 transition arrays. The data presented permit the calculation of the wavelengths of Fe XIX to Fe XXIII emission lines which ar...
Article
Vanadium XVI to XXI emission lines are classified in spectra radiated from a laser produced plasma. They provide additional confirmation to the identification of isoelectronic Fe XX to Fe XXIV lines which are emitted from solar flares.
Article
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Article
Atomic self consistent field calculations are applied to identify Fe VI and Fe VII spectra belonging to the 3p 6 3d n — 3p 5 3d n + 1 transition arrays. Their presence in vacuum spark spectra and absence in solar spectrograms is discussed.
Article
Atomic self consistent field calculations were applied to identity Fe VI and Fe VII spectra belonging to the 3p/sup 6/3d/sup n/ -- 3p/sup 5/ 3d/sup n + 1/ transition arrays. Their presence in vacuum spark spectra and absence in solar spectrograms are discussed. (auth) The hydrodynamic equations for an ideal, inviscid, filly ionized hydrogen gas...
Article
This paper reports recent progress in the classification of the spectra of iron XVIII to XXIV. Emission lines due to these stages of ionisation were reported in the spectra of solar flares by Neupert et al . (1967) who pointed out that the 2 s 2 2 p n –2 s 2 2 p n-1 3d configurations were mainly responsible. The present work verifies this and in ad...
Article
Recent observations of helium-like spectra of carbon, nitrogen and neon are reported, consisting of lines due to the 2p 1P-nd 1D, 2s 3S-np 3P and 2p 3P-nd 3D transitions. Their wavelengths and further wavelengths calculated for these elements and oxygen are listed.
Article
The application of time resolution to a vacuum spark source results II an improved separation of ionization stages. As a result, new multiplets have been classified in the transitions 3p5-3p43d and 3p4-3p33d in the isoelectronic sequences from calcium to iron. This leads to the identification of further members of the intense group of solar lines n...

Citations

... values used in Equation(6). Wavelength values in vacuum were converted to air by the relation[25], the index of refraction of standard air (dry air containing 0.03CO 2 by volume at normal pressure and 15 C T =˚) ...
... Whereas the MBPT results agree (Fawcett & Hayes 1975). The MBPT wavelengths, respectively, are 27.656 and 28.142 Åfor the above two transitions, which deviate from the observed values (27.53 and 28.012 Å) up to 0.46% and 0.47%, but agree well (0.08% and 0.15%) with the more recent experimental values 27.63 and 28.10 Åin the revised identification recommended by the same group (Bromage & Fawcett 1977). Using the above revised observations, the experimental data for s p D 2 2 2 3 2 5 2 should be corrected as 461.8 and 462.1 eV, respectively, with the aid of the known energies of s p D 2 2 2 3 2 5 2 and P 2 3 2 , which agree with our MBPT value of 461.403 eV to within 0.15%. ...
... However, these results are also for LS transitions only. Additional studies have also reported radiative data and energy levels of Cl iii using various calculation methods (Aymar 1973;Huang 1984;Fawcett 1986;Ho & Henry 1987;Berrington & Nakazaki 2002;Morton 2003;Froese Fischer et al. 2006). Huang (1984) used the multiconfiguration Dirac-Fock technique to determine energy levels and transition probabilities for 41 low-lying levels of phosphorous-like ions including Cl iii. ...
... Feldman and Bhatia calculated theoretical-transition wavelengths and energy levels of Fe XXI–Kr XXXI, [6] Ne V, [7] and Ca XV [8] using the Superstructure code. Fawcett [9] presented oscillator strengths and energy levels for allowed n = 2–2 and n = 2–3 transitions in C-like ions between F IV and Ni XXIII based on calculations using the HFR code of Cowan. Zou et al. [10] calculated the 1s 2 2s 2 2p 2 –1s 2 2s2p 3 and 1s 2 2s 2 2p 2 –1s 2 2p 4 transitions of C-like cobalt using the relativistic configuration interaction (RCI) computation program. ...
... and Fawcett [14] reported energy levels and oscillator strengths for some transitions among the 31 levels of the 3s 2 3p 5 , 3s3p 6 and 3s 2 3p 4 3d configurations. For their calculations, Huang et al adopted the multi-configuration Dirac-Fock (MCDF) method of Desclaux [15] and also included configuration interaction (CI) with the additional 3s3p 5 3d, 3p 5 3d 2 , 3s 2 3p 3 3d 2 , 3p 6 3d and 3s3p 4 3d 2 configurations. ...
... For such four-electron systems data calculated by Fawcett (who employs an HXR code with various refinements) are available [9, 101 . The Fawcett data on analogous systems are of lesser detail for Be-like 0, F and Ne [9] than for N [ l o ] . The N data are part of a study in which all radiative decays from the respective levels are given (e.g. from 2p3d 'Po to 2p2, 2s3d, 2p3p, 2s3s, 2~4s). ...
... On the theoretical side, Fawcett et al. [8] calculated the energy levels, oscillator strengths, and wavelengths of S-like ions between S I and Ni XIII using a Hartree-Fock method. Saloman et al. [9] performed fully relativistic multiconfiguration Dirac-Fock (MCDF) calculations for the energy levels of the 3s 2 3p 4 configuration of all S-like ions of atomic number Z = 16-92. ...
... The experimental data have been compiled by Corliss and Sugar [17] and are also available at the NIST (National Institute of Standards and Technology) website http://www.nist.gov/pml/data/asd.cfm. Considering the importance of Ti ions, several calculations have been performed for Ti X – see for example [18] – [23]. A variety of sophisticated methods and codes have been adopted by these workers, but the calculations of [18], [19], [21] and [22] have been confined to the lowest 40 levels of Ti X belonging to the 3s 2 3p, 3s3p 2 , 3s 2 3d, 3p 3 and 3s3p3d configurations. ...
... For such four-electron systems data calculated by Fawcett (who employs an HXR code with various refinements) are available [9, 101 . The Fawcett data on analogous systems are of lesser detail for Be-like 0, F and Ne [9] than for N [ l o ] . The N data are part of a study in which all radiative decays from the respective levels are given (e.g. from 2p3d 'Po to 2p2, 2s3d, 2p3p, 2s3s, 2~4s). ...
... These wavelengths of corrected transitions are now shown in italics. For transitions from 2s 2 2p 3 3d, 2s 2 2p 3 3s and 2s2p 5 to the ground con¢guration (Tables IV, V, and VI), the calculated semiempirical values (SE) from [20] are also given. The total number of possible transitions for some pairs of con¢gurations is quite large. ...