# Maurice GoldmanInstitut de France, Académie des sciences · Section Physique

Maurice Goldman

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86

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## Publications

Publications (86)

Dynamic nuclear polarization, or DNP, refers to the increase of the polarization of nuclear spins in condensed matter, liquid or solid, coupled with electronic spins at low relative concentration, by inducing radio or microwave transitions at frequencies close to the electronic resonance frequency in the external magnetic field. Another described m...

Recently, it was observed that protons in non-conducting solids doped with 1,3-bisdiphenylene-2-phenylallyl (BDPA) or its sulfonated derivative (SA-BDPA) can be polarized through Overhauser effects via resonant microwave irradiation. These effects were present under magic angle spinning conditions in magnetic fields between 5 and 18.8 T and at temp...

Anatole Abragam, a French physicist of Russian origin, made a profound and lasting impact on the field of magnetic resonance, both electronic and nuclear, through his discoveries, contributions and his eminent educational role. In nuclear magnetic resonance (NMR) especially, he brought to the field theoretical rigour and clarity. Many of the most d...

We report on multiple echo measurements in hyperpolarized liquids using optically pumped spin-1/2 noble gas atoms: either 129Xe dissolved in cyclohexane or 3He dissolved in superfluid 4He. An NMR pulse sequence 90◦ − τ − 90◦ (with slice-selective flipping pulses for 129Xe experiments) was used and long echo trains have been observed in the presence...

Anatole Abragam, physicien français, russe de naissance, membre de l’Académie des sciences, a laissé une profonde empreinte dans le domaine de la résonance magnétique, aussi bien électronique (RPE) que nucléaire (RMN), par ses travaux et contributions et son rôle éminent de pédagogue, surtout en RMN, où il a apporté clarté et rigueur théorique. Un...

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The order within proton pairs in organic molecules, resulting from hydrogenation with para-hydrogen, can be transferred in great part to nearby carbon-13 spins through adequate field manipulations. The molecules with hyperpolarized 13 Cthus obtained can be used as new contrast agents of high efficiency in MRI. After a brief presentation of the hydr...

A detailed analysis of nitrogen-15 longitudinal relaxation times in microcrystalline proteins is presented. A theoretical model to quantitatively interpret relaxation times is developed in terms of motional amplitude and characteristic time scale. Different averaging schemes are examined in order to propose an analysis of relaxation curves that tak...

We describe the theory of production of hyperpolarized 13C in small organic molecules, for use as molecular contrast agents in MRI, by a two-step process. The first is a catalyzed hydrogenation with para-hydrogen in a small dc magnetic field under rf irradiation, resulting in a molecular proton pair in the pure para state. The second step converts...

The order within proton pairs in organic molecules, resulting from hydrogenation with parahydrogen, can be transferred in great part to nearby carbon 13 spins through adequate field manipulations. The molecules with hyperpolarized 13C thus obtained can be used as new contrast agents of high efficiency in MRI. After a brief presentation of the hydro...

Para-hydrogen can be used for creating highly polarized nuclei, exceeding the thermal equilibrium polarization by several orders of magnitude. The Para-hydrogen Induced Polarization (PHIP) phenomenon discovered in 1986 by Bowers and Weitecamp [1], creates a non-equilibrium spin order that can be transformed into polarization. The transfer of this s...

Mechanical rotation of a sample at 54.7 degrees with respect to the static magnetic field, so-called magic-angle spinning (MAS), is currently a routine procedure in nuclear magnetic resonance (NMR). The technique enhances the spectral resolution by averaging away anisotropic spin interactions thereby producing isotropic-like spectra with resolved c...

A history of NMR: around its first actors... and after This is a description of the evolution of NMR, from its beginning to the present developments and applications, in relation with the tools and concepts available at each time. NMR, now mostly a tool of very diverse applications, in majority for chemistry and medicine, is essentially a disciplin...

A thermal mixing of the 19F and 7Li Zeeman reservoirs in lithium fluoride containing F centres has been observed at high magnetic fields and low temperatures (g beta H>kt), and its rate measured as a function of NMR frequency and electronic polarization. The mixing, much faster than spin-lattice relaxation, is through the electronic spin-spin reser...

When, in the method MAS, part of the sample is at the edge of the coil so as to experience a partly radial RF field, this part gives rise during the sample spinning to spectra shifted by –1 and +1 times the spinning frequency, which are superimposed on the normal spectra with possible sidebands due to the modulated interactions, anisotropic chemica...

A spin hamiltonian formalism is used to develop the theory of spin-lattice relaxation by the direct process in a system S=1/2, I=1/2 with hyperfine coupling in cubic symmetry. It is shown that when J is a good quantum number the probabilities for the direct ( mod Delta m mod =1, Delta M=0) as well as the 'skew' ( mod Delta (m+M) mod =0,2) transitio...

The theory of thermal mixing between nuclear Zeeman interactions and electronic spin-spin interactions of impurities in dielectric solids, used to interpret the mixing between the Zeeman interactions of two nuclear spin species as the result of their separate coupling with the electronic spin-spin reservoir. The predictions of the theory are compar...

After a general introduction, two sections are devoted to a survey of the theories of spin temperature and of nuclear relaxation in solids. This is followed by a short section on the so-called well-resolved solid effect, and a much more detailed one on DNP by thermal mixing in the non-linear low spin-temperature domain. One then analyses the variou...

The onset of nuclear antiferromagnetism has been observed in lithium fluoride 7Li19F. The ordering is due to the magnetic-dipole interactions between nuclei so that lithium fluoride becomes the second substance in which such ordering has been sought experimentally, and the first to exhibit an antiferromagnetic state in which two species of nuclear...

The existence of sidebands at +/-v(r) in MAS spectra due to the radial component of the RF field at the edges of the coil is described theoretically and illustrated experimentally. The height of the radial-field sidebands does not depend on the spinning speed and may contribute significantly to the intensity of -1 spinning sideband of MAS modulated...

The authors describe the theoretical prediction of a rotating transverse helical ordering of the 19F nuclear spins in CaF2, produced by adiabatic demagnetisation in high field, and the experimental study of its properties: resonant polarisation of the 43Ca probe nuclei, the shape of the absorption signal, transverse susceptibility, spin-lattice rel...

For pt.I see ibid., vol.19, p.2275 (1986). The authors describe two approximate methods for the study of rotating transverse helimagnetism in high field in CaF2: the random phase approximation (RPA) and a physical model based on the fact that the Weiss field at any nuclear site is produced by distant spins. Both methods predict the helical structur...

The 15N steady-state magnetization in the presence of off-resonance rf irradiation is an analytical function of the T1/T2 ratio and of the angle between the 15N effective field axis and the static magnetic field direction. This relation holds whatever the relaxation mechanisms due to motions on the nanosecond time scale, and the size of the spin sy...

It is shown that, by using an RF coil of suitable shape, sample spinning around an axis parallel to the main field produces a shift of the NMR resonance frequency. This effect is experimentally verified on1H and119Sn in liquid samples. A general discussion of sample spinning and frequency shift is given in connection with the rotating-frame picture...

A theoretical analysis is made of several problems of nuclear magnetic resonance for nuclei subjected to sudden frequency jumps and for which the previously published method of spin-linked evolution proves convenient, leading to particularly simple and transparent calculations. These are: free induction decay (FID) in the presence of a randomly mod...

We describe the nuclear relaxation of protons by paramagnetic centers in glassy solutions of polymers. Both the protons and the paramagnetic radicals are on the polymers, and the solvent is fully deuterated. Two cases have been analyzed, that when the relaxing centers are randomly distributed, and that when each polymer has a single center grafted...

We analyse the effect of the average dipolar field on an NMR J-doublet. This effect is twofold: an overall shift of the spectrum and a cross-precession between its components, which results in different intensities for these components, whose ratio depends on the pulse angle. Experiments on di-isopropyl ether at 500 MHz confirm these predictions. I...

It is shown that, by using an RF coil of suitable shape, sample spinning around an axis parallel to the main field produces a shift of the NMR resonance frequency. This effect is experimentally verified on1H and119Sn in liquid samples. A general discussion of sample spinning and frequency shift is given in connection with the rotating-frame picture...

A theoretical model is presented for the analysis of NMR in the liquid state, when the NMR parameters are modulated by chemical exchange. This model, based on the sudden jump approximation, describes directly the free induction decay signals, without analysing first their derivative. This formalism, which is extremely simple, applies in particular...

A new way to explore the conformation and dynamics of medium-sized molecules in solution has been recently proposed. This powerful quantitative approach is based on the use of a strong off-resonance spin-lock pulse for the mixing period of the classical ROESY scheme. Here several improvements of the method are presented, resulting in an increase of...

The method of off-resonance ROESY consists of studying relaxation in the presence of a strong off-resonance irradiation. Its theory is developed under very general assumptions and its advantages are described over more standard methods: suppression of HOHAHA transfers and possibility by the appropriate choice of the effective field to check the onl...

A method is described for the measurement of the steady-state nuclear magnetization under strong off-resonance RF irradiation as a function of the angle between the external field and the effective field in the rotating frame. For purely dipolar relaxation between homonuclear spins under isotropic Brownian molecular rotation, its variation with the...

By using a strong off-resonance irradiation in the ROESY sequence, one can study the relaxation without the drawbacks of NOESY (cancelation of the dipolar cross-relaxation rates) or of ROESY (angular dispersion, coherence transfer by indirect interactions). Moreover constraints on the dynamics of the system can be obtained by an appropriate choice...

The steady-state magnetizations of homonuclear spins experiencing a strong off-resonance irradiation are aligned with the effective field. Their amplitude is a function of the correlation time and of the angle between the static field and the effective field in the rotating frame. By varying the latter, one can determine the effective local correla...

URL: http://www-spht.cea.fr/articles/s94/048

Nous discutons la forme du signal de precession libre dans le domaine des mouvements intermediaires dans le cas ou la valeur moyenne des interactions dipolaires s'annule. Un modele simple decrit ici a permis de rendre compte avec un bon accord de la variation de la forme du signal de precession libre avec la temperature pour un monocristal. Dans ce...

In dynamic NMR studies of a spin system, relaxing under off-resonance rf irradiation, inherent drawbacks of NOESY and ROESY (cancellation of cross-peaks, magnetization transfer through indirect interactions) are suppressed. For two different angle values between static field and effective field in the rotating frame, additional constraints on the s...

The steady-state magnetization of homonuclear spins, under strong off-resonance rf irradiation, is aligned with the effective field in the rotating frame. Its amplitude is a function of the angle between the effective and static fields, and of the dynamics of the system. For purely dipolar relaxation and isotropic Brownian rotation, it corresponds...

A simple approximation, based on the strong collision model, is used to describe the influence of motion on the nuclear FID. Experiments performed on a single crystal of hexamethylethane yield results in remarkably close agreement with that model.

Ferromagnetism of 19F nuclear spins in a monocrystalline KMgF3 sample has been observed by NMR in the presence of a high magnetic field and in the microkelvin temperature range. The three 19F spins of one crystalline cell are equivalent when the field is along the [111] axis of the crystal and inequivalent for the field along the [100] axis. At neg...

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An antiferromagnetic order of the nuclear spins of 7Li and 1H is produced by Dynamic Polarization followed by Adiabatic Demagnetization in the Rotating Frame. The magnetic field is parallel to a [001] direction, and both positive and negative spin temperatures are investigated. The ordering is studied by means of Nuclear Magnetic Resonance and neut...

The theory of magnetic relaxation of each line of a doublet in a pair I-S of unlike nuclei with indirect coupling, in the presence of both dipolar I-S coupling and anisotropic chemical shift, in the frame of density-matrix master-equation formalism is derived. An experimental scheme for accurately measuring differential line broadening in the doubl...

We present a new NMR method for the investigation of rotational Brownian motion based on the appearance of dipolar relaxation as the particles rotate. Our experimental results obtained on submicrometer polystyrene spheres in water confirm quantitatively the basic laws of rotational Brownian motion. The effects of hydrodynamic interactions and long-...

New methods for measuring the energy and the temperature of the secular dipole-dipole interactions of nuclear spin systems in high field are described. These methods are valid at all temperatures and even in the presence of magnetic ordering. The energy is measured by monitoring its variation in the course of a controlled saturation. The temperatur...

Experimental evidence for the production of a nuclear dipolar magnetic ordering in a high external field, where the nuclear spins are oriented at right angle to the field in the form of a helix which precesses around the field at the Larmor frequency, is presented.

We derive an approximate theory for the spin diffusion tensor in a rare nuclear spin species imbedded into an abundant one, with special reference to 43Ca in CaF2. The usefulness of the theory is examplified by the description of an investigation of ferromagnetism with domains of the 19F spins, where the knowledge of the 43Ca spin diffusion constan...

This work is a theoretical and experimental study of the field-entropy phase diagram of a nuclear dipolar antiferromagnet in CaF2. There is a large region in this plane where the state of the system is a « mixed » structure in which paramagnetic and antiferromagnetic domains coexist in well defined proportions. The theoretical predictions, based on...

We develop a theoretical analysis of the influence of domains in ordered nuclear spin systems on the neutron diffraction pattern. In a first part, we show that the variation with crystal orientation of the 2-dimensional distribution of diffracted neutron intensities yields the correlation function of the domain distribution. In a second part we est...

We describe the detection by neutron diffraction of two new ordered phases in LiH, produced by nuclear adiabatic demagnetization in a high field parallel to a [110] crystalline axis. The phases are antiferromagnetic at positive temperature and ferromagnetic at negative temperature. A 2-dimensional neutron detector reveals that the domains are aniso...

Antiferromagnetic structures of nuclear spins of 7Li and 1H have been produced in a single crystal of lithium hydride by the now standard method of dynamic nuclear polarization followed by an adiabatic demagnetization in the rotating frame (ADRF). The (110) Bragg reflection, characteristic of an antiferromagnetic superstructure, has been observed b...

This article reviews the subject of magnetic ordering in nuclear spin systems subjected to dipole-dipole interactions. This study has been developed so far in only one laboratory, the laboratory of Nuclear Magnetism at Saclay. The impetus was given by Professor A. Abragam, who invented a method for producing the very low temperatures necessary for...

We have measured the 43Ca-19F dipolar energy in CaF2, as deduced from the first moment of the 43Ca resonance signal, as a function of the fluorine-fluorine energy. The Ca-F energy, which depends on the local longitudinal susceptibility of the fluorine spins, is theoretically expected to peak at the paramagnetic-antiferromagnetic transition. Such a...

We consider the influence of antiferromagnetic nuclear ordering on the spin-lattice relaxation of the nuclear dipolar energy by paramagnetic impurities. The predictions are different depending whether the correlation time τ c of the spin-lattice coupling is shorter or longer than T2 . When τc << T2, relaxation is slower in the antiferromagnetic tha...

We develop the formalism of calculation of physical quantities in a paramagnetic nuclear spin species. The calculations are done for a system of spins at thermal equilibrium in the rotating frame, where they are subjected to Zeeman and secular dipolar interactions. The formulae are valid to all orders with respect to Zeeman interactions and corresp...

We describe a method of measurement of secular dipolar energy in nuclear spin systems which is valid at all temperatures and even in the presence of nuclear magnetic ordering. It is based on the measurement of the first moment of the nuclear absorption signal at low rf level.

We use in this work the restricted-trace approximation to predict several properties of nuclear antiferromagnetic structures : sublattice magnetization, longitudinal and transverse susceptibilities. This study is specialized to a particular antiferromagnetic structure, observed in calcium fluoride. Although not perfect, the predictions of this theo...

We describe in this article the principles of production and observation of magnetic ordering in systems of nuclear spins subjected to dipole-dipole interactions. The cooling necessary for producing ordering, which concerns only the nuclei, is obtained by a two-step process: dynamic polarization in a high field followed by adiabatic nuclear demagne...

We present measurements of the transverse and longitudinal susceptibilities as functions of dipolar energy, in the nuclear antiferromagnetic phase of 19F spins in CaF2, obtained by adiabatic demagnetization in the rotating frame at negative temperature and with the magnetic field applied along [100].

This paper reports the polarization of the 43Ca nuclei (natural abundance of 0.13%) in CaF2 by a three-step process: dynamic nuclear polarization of the 19F nuclei, adiabatic demagnetization in the rotating frame of these spins, and finally rf thermal mixing, in an appropriate rotating frame, of the 43Ca Zeeman energy with the nuclear dipolar inter...

We have developed the formalism of spin-lattice relaxation theory in a nuclear spin system subjected to rf irradiation either close to or far from resonance. In the former case, when there is a single spin temperature in the rotating frame, one obtains simple formulas for relaxation through a spin-lattice coupling of correlation time ${$\tau${}}_{c...

We have studied both theoretically and experimentally the variation of NMR absorption lineshape as a function of nuclear polarization in systems with one spin species. General expressions are given for the first and second moments M1 and M1, as well as the values of M3 and M4 in the special case of spherical samples of spins forming a simple cubic...

Because of the smallness of dipolar interactions between nuclear spins in diamagnetic solids, temperatures of the order of 10-6 K or less are required to produce nuclear magnetic ordering. In our study, we cool only the nuclear spins in a two-step process. The spins are first polarized in high field by the 'solid effect’ to an equivalent temperatur...

In most diamagnetic substances the strength of dipolar interactions between nuclear spins is such that temperatures of the order of a microdegree or less must be obtained for cooperative effects to take place. Rather than cooling the whole sample we have cooled directly the nuclear spins of <sup>19</sup>F in CaF 2 , which are thermally isolated for...

When one induces transitions in an electronic spin system whose résonance line is broadened by hyperfine interactions, population transfers take place among the various spin packets. This effect is important only when the equilibrium electronic polarization is high. It manifests itself : 1) By a modification of the shape of the observed line ; 2) B...

We study both theoretically and experimentally the magnetization loss of a nuclear spin system irradiated with a rf field under a linear field sweep through the resonance. Two limiting cases are considered. The first is that of a slightly saturating passage, in which the loss is simply related to the rf field amplitude, a fact which allows an easy...

Fluorine dynamic polarizations of 45% have been obtained by the solid effect in CaF2: U3+ at 1.05°K and 27 kG. From the experimental results, it seems that the polarization is partly limited by a phonon-bottleneck. The fluorine resonance line is strongly asymmetric.

The present work describes a method of dynamic nuclear polarization by means of cycles of thermal mixing in three steps : cooling of an intermediate system, thermal mixing in zero field with the spins to be polarized, adiabatic magnetization. This method puts in action in separate steps phenomena which are totally or partially intermingled in the m...

This work reports proton spin-lattice relaxation-time measurements performed as a function of temperature and magnetic field on a single crystal of paradibromobenzene, at liquid-helium temperatures and at room temperature. Strong evidence is displayed that at low temperature the proton spin-lattice relaxation is controlled by one kind of paramagnet...

The theory of Provotorov is made use of for studying the shape of the nuclear magnetic resonance signals recorded after lock-in detection and the saturation effect of the field modulation. The analysis is developed under restrictive conditions which simplify the calculations, but correspond nevertheless to practical experimental procedures. It perm...

Proton magnetic resonance spectra have been observed for both monocrystalline and polycrystalline samples of trichloracetic acid. They provide evidence that the acid is a dimer with a proton-proton distance of 2.56 ± 0.02 Å.The spectrum of the single crystal was studied as a function of orientation in the magnetic field and indicates the presence o...