Showing papers in "Journal of the Physical Society of Japan in 1962"
TL;DR: The notion of cumulants and cumulant functions was introduced in this paper, where a moment generating function of a set of stochastic variables defines the cumulus or the semi-invariants and the cumULant function, and the definition of average may be greatly generalized as far as the condition of the average of unity is unity.
Abstract: The moment generating function of a set of stochastic variables defines the cumulants or the semi-invariants and the cumulant function. It is possible, simply by formal properties of exponential functions, to generaiize to a great extent the concepts of cumulants and cumulant function. The stochastic variables to be considered need not be ordinary c -numbers but they may be q -numbers such as used in quantum mechanics. The exponential function which defines a moment generating function may be any kind of generalized exponential, for example an ordered exponential with a certain prescription for ordering q -number variables. The definition of average may be greatly generalized as far as the condition is fulfilled that the average of unity is unity. After statements of a few basic theorems these generalizations are discussed here with certain examples of application. This generalized cumulant expansion provides us with a point of view from which many existent methods in quantum mechanics and statistical mec...
1,431 citations
TL;DR: The level spacing of quantized electronic states becomes fairly large in very fine particles as mentioned in this paper, and the thermal properties may show considerable deviations from the normal bulk values for such fine particles.
Abstract: The level spacing of quantized electronic states becomes fairly large in very fine particles. For instance, it will be comparable to k T at T =1°K if the linear dimension of a particle is 50 A or so. Thermal properties may show considerable deviations from the normal bulk values for such fine particles. The heat capacity will be reduced to about two-thirds and the paramagnetic susceptibility may be enhanced. Even more important effects are expected for relaxation processes. They are discussed briefly, but more detailed treatments will be given in a forth-coming paper.
876 citations
Journal Article•
TL;DR: A joint air shower experiment is being set up and is near full operation at an altitude of 5,200 m in Bolivia as discussed by the authors, where the principal objectives and a brief account of the equipment are given.
Abstract: A joint air shower experiment is being set up and is near full operation at an altitude of 5,200 m in Bolivia. The principal objectives and a brief account of the equipment are given. (auth)
484 citations
TL;DR: In this article, the co-operative effect of electron correlation and random lattice in the impurity conduction of semiconductors is investigated in terms of the Green's function with in the frame-work of Hartree-Fock approximation.
Abstract: The co-operative effect of electron correlation and random lattice in the impurity conduction of semiconductors is investigated in terms of the Green's function with in the frame-work of Hartree-Fock approximation. There appear magnetic states embedded in the metallic impurity band, being located at those impurity sites which are relatively isolated from other sites. The fraction of these magnetic sites is estimated to be of the order of ten percents, being a decreasing function of impurity concentration. The magnetic moment of the localized spin is calculated with a method which is different from the conventional one. Treating the localized spins as collective modes which act upon the individual electrons of the impurity band as potential fluctuation (in space and in time), we have calculated the effect of magnetic field or spin ordering on the electrical resistivity.
231 citations
TL;DR: The stacking fault energy in an alpha-phase solid solution with face-centered cubic structure usually decreases continuously with the increasing concentration of solute atoms as mentioned in this paper, and the width of an extended dislocation should increase indefinitely if the stacking faults energy becomes lower than a negative value.
Abstract: An experimental evidence was given for the segregation of solute atoms to stacking faults in alpha-brass. The stacking fault energy in an alpha-phase solid solution with face-centered cubic structure usually decreases continuously with the increasing concentration of solute atoms. The solute atoms in that alloy tend to segregate to the stacking faults due to chemical interaction. A simple calculation indicates that the solute atoms segregate to such a high concentration as the stacking fault energy becomes a negative value with considerable magnitude, provided that the concentration of solute atoms is in thermal equilibrium at rather low temperature. The width of an extended dislocation should increase indefinitely if the stacking fault energy becomes lower than a negative value. Alpha-brass with 30% zinc, which was annealed at 120°C and 150°C for a week and two days, respectively, after cold-work reveals extended dislocations with extremely wide stacking faults of the order of several microns. Meanwhile,...
194 citations
TL;DR: In this article, the surface of barium titanate was found to change substantially when heated above 500°C in air and vacuo, invalidating their evidence for an unusually high Curie temperature of their anomalous surface layer.
Abstract: Thin single crystal films of barium titanate prepared by chemical thinning of single crystal plates are studied by transmission electron microscopy and electron diffraction. The films as thin as 1000 A are found to have the same lattice parameters as the bulk crystals, giving no evidence for the existence of the anomalous surface layer proposed by Kanzig et al. The surface of barium titanate is found to change substantially when heated above 500°C in air and vacuo, invalidating their evidence for an unusually high Curie temperature of their anomalous surface layer. Ferroelectric 90° and 180° domains are observed by electron microscopy. The contrast of 90° domains is simple diffraction contrast. The contrast of 180° domains is due to the failure of Friedel's law, which is known to be possible to take place in electron diffraction by dynamical diffraction effect. Dislocations, tracks of fission fragments from uranium and their interaction with domains are observed.
173 citations
TL;DR: The experimental data of nucleon-nucleus collisions of energies around 100 GeV have been analyzed in this article, showing that the transverse momentum, p T, of shower particles is also an adequate parameter to analyse the nucleon nucleus collision.
Abstract: The experimental data of nucleon-nucleus collisions of energies around 100 GeV have been analysed. It is pointed out that the transverse momentum, p T , of shower particles is also an adequate parameter to analyse the nucleon- nucleus collision. The transverse momenta, both in the average value and in the distribution, are similar to the case of the nucleon-nucleon collision. Both the median angle and the average number of shower particles increase with the number of heavily ionizing prongs, N h . The latter observations exclude the possibility that, for primary energy at least up to several tens GeV, the target of events with high N h is effectively a single nucleon. Although conclusive evidence to reject the model of cascade development (of nucleon-nucleon and pion-nucleon collisions) is not presented, this model seems to be disagreement with the data of p T . The existing data can reasonably be explained by the model of a simultaneous collision between an incident nucident nucleon and a lump of nucleon...
155 citations
TL;DR: In this paper, the dielectric constants of SrTiO₃/ were examined in three directions: STA110!, STA111!, and STA100!. (W.D.M.)
Abstract: It has been reported that SrTiO₃/ becomes ferroelectric below about 50 deg K. When SrTiO₃ is compared with well known ferroelectrics such as BaTiO₃, remarkable contrasts are found in their dielectric properties. The dielectric constants are examined in three directions: STA110!, STA111!, and STA100!. (W.D.M.)
136 citations
TL;DR: In this paper, it was shown that at least 95% of the Ti ions are located on the B layer but that they are not ordered within the layer, which is interpreted as a consequence of inhomogeneity in the magnetic structure.
Abstract: The solid solutions (1- x )FeTiO 3 - x Fe 2 O 3 exhibit strong ferromagnetic moments in the composition range 0.1< x <0.6. In this region cation ordering is thought to occur such that the Fe 2+ and Ti 4+ ions occupy alternate (111) layers, thus forming sublattices A[ x Fe 3+ , (1- x )Fe 2+ ] and B[ x Fe 3+ , (1- x )Ti 4+ ]. A neutron diffraction study shows that at least 95% of the Ti ions are located on the B layer but that they are not ordered within the layer. The temperature dependence of the magnetic intensities of a number of ferrimagnetic phases reveals that both sublattice moments, at zero magnetic field, fall considerably short of the theoretical values. In addition, Mossbauer patterns indicate that paramagnetic behavior persists over a rather wide temperature range below the Neel temperatures of solid solutions in which x =0.21 and x =0.33. These results are interpreted as a consequence of inhomogeneity in the magnetic structure, due to competing interactions as a result of the Ti ions being dis...
135 citations
TL;DR: In this paper, the epitaxial growth of Ni, Cu, Ag, Au and Al on NaCl crystals cleaved in vacuum has been studied, and it was shown that the (1)-plane parallel to the substrate at the substrate temperature of 100°C improves with the degree of vacuum.
Abstract: The epitaxial growth of Ni, Cu, Ag, Au and Al on NaCl crystals cleaved in vacuum has been studied. When the crystals are cleaved in ordinary high vacuum (10 -4 –10 -5 mmHg), a considerable lowering of the epitaxial temperatures for the parallel epitaxy takes place for the first four metals, as compared with the case in which the crystals are cleaved in air. The temperature differences due to this lowering are 270°C for Ni, 250°C for Cu, 150°C for Ag, and 120°C for Au. Al has been found for the first time to form single crystal films with the (111)-plane parallel to the substrate at the substrate temperature of 100°C. When the degree of vacuum is improved to ultrahigh vacuum (10 -7 –10 -9 mmHg), on the other hand, the (001) preferred orientation deteriorates and the (111) preferred orientation appears for Cu, Ag and Au, the latter orientation becoming conspicuous with rising temperature for Au and Ag, while no considerable change arises for Ni and Al with the improvement of the degree of vacuum.
128 citations
Journal Article•
TL;DR: In this paper, 19 3.3m/sup 2/plastic scintillation detectors in a hexagonal array covering 2 km/sup 1/2/ were used to record the lateral distribution of particle density, proportion of penetrating particles, variation of shower intensity and shower size with atmospheric depth, the primary cosmic ray energy spectrum, isotropy of primary cosmic radiation, and the largest shower recorded.
Abstract: Nineteen 3.3-m/sup 2/ plastic scintillation detectors in a hexagonal array covering 2 km/sup 2/ were used in this study. Methods of recording and analyzing data are discussed, and results are presented on the following: lateral distribution of particle density, the proportion of penetrating particles, variation of shower intensity and shower size with atmospheric depth, the primary cosmic ray energy spectrum, isotropy of primary cosmic radiation, and the largest shower recorded. (A.G.W.)
TL;DR: The radio emission from solar flares is of special interest in the study of geomagnetic storms and solar cosmic rays because it gives a direct indication oi the passage of ionized streams of gas through the Sun's atmosphere as discussed by the authors.
Abstract: The radio emission from solar flares is of special interest in the study of geomagnetic storms and solar cosmic rays because it gives a direct indication oi the passage of ionized streams of gas through the Sun's atmosphere. The nature of these emissions is reviewed in a general way. (auth)
TL;DR: In this article, the magnetic properties of Mn 4 N compounds, partially substituted by In and Sn respectively, are studied by a newly devised magnetic torsion balance, and the band scheme of γ-Mn is also discussed in connection with that of NM 4 N.
Abstract: In order to obtain some informations on the electronic structure of Mn 4 N, the magnetic properties of Mn 4 N compounds, partially substituted by In and Sn respectively, are studied by a newly devised magnetic torsion balance. These compounds show very complicated temperature- and composition-dependences of saturation magnetization and have the magnetic susceptibilities nearly independent of temperature at far above the Curie temperatures. Moreover, the composition dependence of the magnetic moment varies remarkably with the species of substituent metals. These facts may be explained in terms of an intuitive band scheme which leads to the variation of the magnetic moment on each sublattice with temperature. The band scheme of γ-Mn is also discussed in connection with that of Mn 4 N
TL;DR: In this article, the magnetic properties of FeTiO 3 containing less than 50 mole percent of Fe 2 O 3 have been re-examined between 2°K and room temperature by means of a Cioffi-type automatic fluxmeter.
Abstract: The magnetic properties of FeTiO 3 containing less than 50 mole percent of Fe 2 O 3 have been re-examined between 2°K and room temperature by means of a Cioffi-type automatic fluxmeter. It was confirmed that each specimen has a low-temperature transition point, which decreases in temperature with increasing content of Fe 2 O 3 . Above the transition temperature the specimens with 8 and 12 mole % Fe 2 O 3 show superparamagnetic behavior. By analysis of the superparamagnetic magnetization curves, the sizes of the superparamagnetic clusters were determined. The average size of clusters in these crystals is found to be explained by a simple assumption that one Fe 3+ ion which enters into the Ti layers of ilmenite alignes the spins of 9 nearest neighbour Fe ions parallel by a superexchange interaction. The complete phase diagram of the ilmenite rich side of the solid solution, as revised by the present study, is presented.
TL;DR: In this article, the angular distributions of the reaction Na/sup 23/(p, alpha )Ne/sup 20/ and K/sup 39/(p and alpha )Ar/sup 36/ were measured at 6.9, 7.1 and 7.3 Mev, respectively, using a semiconductor detector.
Abstract: Angular distributions of the reactions Na/sup 23/(p, alpha )Ne/sup 20/ and tates of the residual nuclei were measured at 6.9, 7.1 and 7.3 Mev of the incident proton energy, respectively, using a semiconductor detector For the reaction Na/sup 23/(p, alpha )Ne/sup 20/ the angunlar distributions of these alpha particles are almost 90 deg unsymmetrical at 7.1 Mev of the incident proton energy, and are slightly unsymmetrical about 90 deg at 7.3 and 6.9 Mev. For the reaction K/sup 39/(p, alpha )Ar/sup 36/,the angular distributions are almost 90 deg symmetrical at all energies of the incident protons. It is considered that the reactions Na/sup 23/(p, alpha )Ne/sup 20/ and K/sup 39/(p, alpha )Ar/sup 36/ leading to the ground and first excited states of the residul nuclei, at around; Mev of incident proton energy, occur through a compound nucleus process, and in the former reaction the number of the compound states excited by the approximately 7-Mev protons are probably not so many as to justify the statistical assumption.
Journal Article•
TL;DR: The importance of doing experiments with high-energy cosmic-ray neutrinos is discussed in this article, where an experimental arrangement for the experiments is suggested, and reactions of neutrino and antineutrinos that might yield useful information are considered.
Abstract: The importance of doing experiments with high-energy cosmic-ray neutrinos is discussed. An experimental arrangement for the experiments is suggested, and reactions of neutrinos and antineutrinos that might yield useful information are considered. Event frequencies to be expected are estimated. (A.G.W.)
TL;DR: Torque measurements on single crystals of Gd (hexagonal structure) are made at 10 to 350 deg K and at magnetic fields up to 20 kOe, and Fourier analysis of the measured torque curves is used to determine the anisotropy constants as discussed by the authors.
Abstract: Torque measurements on single crystals of Gd (hexagonal structure) are made at 10 to 350 deg K and at magnetic fields up to 20 kOe, and Fourier analysis of the measured torque curves is used to determine the anisotropy constants. (T.F.H.)
TL;DR: In this paper, an alternative interpretation of cyclotron resonance experiment is presented, taking into account the incompleteness of circular polarization of microwave in the experiment done by Galt, Yager and Dail, and it is shown that the values of k z which give absorption peaks are k z = 0 for holes and E 2 = E 3 for electrons.
Abstract: Landau levels and their eigenfunctions are calculated for the band model of Slonczewsky and Weiss by using Kohn-Luttinger's method. Owing to the interband effect, the energy levels do not agree with semiclassical energy levels. The theory of cyclotron resonance absorption is developed on the basis of obtained energy levels and eigenfunctions. Taking into account the incompleteness of circular polarization of microwave in the experiment done by Galt, Yager and Dail, an alternative interpretation of cyclotron resonance experiment is presented. It is shown that the values of k z which give absorption peaks are k z =0 for holes and E 2 = E 3 for electrons, instead of Nozieres's interpretation. The values γ 0 2 /γ 1 =31 eV and γ 0 2 / E f =317 eV are obtained for band parameters to fit the experimental data. The possibility of determining γ 1 directly from magneto-optical effect is also discussed.
TL;DR: In this article, the magnetic properties of all compounds with B8 type structure in transition elements-tin systems were investigated, and it was shown that Mn 1.5+ x Sn(0≤ x ≤ 0.3) was ferrimagnetic having the Curie temperature at about 260°K, Fe 1.3 Sn and CoNiSn were paramagnetic above the liquid nitrogen temperature.
Abstract: The magnetic properties of all compounds with B8 type structure in transition elements-tin systems were investigated, and it was shown that Mn 1.5+ x Sn(0≤ x ≤0.3) was ferrimagnetic having the Curie temperature at about 260°K, Fe 1.3 Sn and CoNiSn were ferromagnetic having the Curie temperature at about 676°K and above 850°K, respectively, and Co 1.4 Sn Ni 1.4 Sn were paramagnetic above the liquid nitrogen temperature. The magnetic moment per mol decreases as the manganese content increases, and the magnetic moments of the compounds with the same structure in various transition metals-tin systems are explained by the assumption that the moments of iron, cobalt and nickel are successively less by one Bohr magneton than that of manganese.
TL;DR: In this paper, the effect of Fe 3+ ions on the line width of Cr 3+ spin resonance in K 3 (Cr 0.01 Fe x Co 0.99-x (CN) 6) was studied with varying the concentration of Fe (or Co) ions.
Abstract: The effect of Fe 3+ ions on the line width of Cr 3+ spin resonance in K 3 (Cr 0.01 Fe x Co 0.99- x (CN) 6 is studied with varying the concentration of Fe (or Co) ions. At room temperature the resonance lines of Cr 3+ ions have small widths in spite of coexistence of paramagnetic ions Fe 3+ . However, with decreasing temperature, line widths of Cr 3+ ions are broadened and the resonance fields are shifted to lower fields. The widths at lowest temperatures exceed the calculated dipolar width, suggesting the existence of certain amounts of exchange coupling between Cr 3+ ions and Fe 3+ ions. The temperature variations of the line widths and the shifts are reasonably interpreted in terms of the random modulation of the interactions between Cr 3+ ions and Fe 3+ ions by the rapid spin-lattice relaxation of Fe 3+ ions following the generalized theory of magnetic resonace by R. Kubo and K. Tomita (J.Phys. Soc. Japan 9 (1954) 888).
TL;DR: In this article, the crystal structure of BS 2 type, in relation to B8 1 type, is discussed with the assumption of covalent bond between the dissimilar atoms in the honey-comb layer lattice of this structure.
Abstract: The crystal structure of BS 2 type, in relation to B8 1 type, is discussed with the assumption of covalent bond between the dissimilar atoms in the honey-comb layer lattice of this structure. The covalent bond is interpreted in terms of hybridized orbitals. This concept explains the stability of the crystal structure and the fact that the most of constituent metalloid atom in B8 2 type of structure belong to IVb group. Further-more this description leads us to an important conclusion that the spin moment of the constituent transition metal atom is governed by a simple rule. This rule is discussed on the basis of the experimental results made by author and is found to explain satisfactorily the results for magnetic moment. Then D8 8 type of structure is also discussed as a variant of B8 2 type of structure.
TL;DR: In this article, the authors measured the absorption of Fe 57 in α-Fe 2 O 3 as a function of temperature from 100°K to 1050°K and found that a steep change of the energy shift e due to quadrupole interaction was found at about 260°K.
Abstract: Mossbauer absorption by Fe 57 in α-Fe 2 O 3 has been measured as a function of temperature from 100°K to 1050°K. In the hyperfine spectra, a steep change of the energy shift e due to quadrupole interaction was found at about 260°K. The ratio of e at 100°K to that at 300°K is -2.0±0.4. This value corresponds to the ratio of (3cos 2 θ-1) below and above the transition temperature, if we assume that the direction of the principal axis of the electric field gradient at the iron nucleus is parallel to the c axis. A careful observation of the shape of the absorption line near the transition temperature showed that each line consisted of doublet respectively. This fact reveals that the transition temperature of α-Fe 2 O 3 used in the present experiment varies locally from 220°K to 270°K. The value of e 2 q Q obtained at about 260°K is (+0.084±0.008) cm/sec=(+9.7±0.9) Mc/sec. Although there were fairly large errors in the obtained values of e 2 q Q , thefild gradient seemed to increase slowly with temperature fro...
TL;DR: In this paper, the electronic specific heat and spin susceptibility of Cr-Fe and Cr-V alloys are calculated at arbitrary temperatures, and the calculated electronic specific heats satisfactorily agree with the experimental results, whereas the calculated spin susceptibilities are smaller.
Abstract: Electronic specific heats for various transition metals at higher temperature are deduced from experimental results. It is pointed out that the transition metals with small values of paramagnetic susceptibility and coefficient of low temperature specific heat, γ 0 , have larger values of the electronic specific heat than the extrapolation of γ 0 T , and the metals with large values of these have smaller values of the electronic specific heat than the extrapolation of γ 0 T , at higher temperatures. With use of electronic state density determined from the data of γ 0 , for Cr-Fe and Cr-V alloys, the temperature variations of electronic specific heat and spin susceptibility of Cr are calculated at arbitrary temperatures. The calculated electronic specific heats satisfactorily agree with the experimental results, whereas the calculated spin susceptibilities are smaller than the experimental results. It is pointed out that the main difference is attributable to the orbital paramagnetic susceptibility.
TL;DR: In this paper, the flow formation in Couette motion of an electrically conducting, viscous and incompressible fluid in a transverse magnetic field is studied. But the analysis is limited to the case of small magnetic Reynolds number.
Abstract: Flow formation in Couette motion of an electrically conducting, viscous and incompressible fluid in a transverse magnetic field is studied. The analysis is limited to the case of small magnetic Reynolds number. By the method of Laplace transform the expressions for the velocity distribution and skin friction are obtained. Numerical results show that the flow is retarded and, there fore, the skin friction increases by the effect of the magnetic field. However, at the commencement of motion the manner of flow formation is hardly affected by the magnetic field.
TL;DR: In this paper, the radial distribution method of electron diffraction was used to study the properties of nickel and cobalt crystallites and found that the lattice constant and the amplitude of thermal vibration are the same as those of massive cobalt crystals but anomalous neighbours of h.p.c. type are found.
Abstract: Evaporated films of nickel and cobalt formed on amorphous bases were studied by the radial distribution method of electron diffraction. The mean thickness of films was the order of 10A. Such thin films are not continuous and consist of crystallites with size of the order of 10A. For nickel crystallites, the lattice constant and the amplitude of thermal vibration are the same as those of massive crystals but anomalous neighbours of h.c.p. type are found. These results are the same as those for silver which were studied in the previous work (J. Phys. Soc. Japan 13 (1958) 1015). For cobalt crystallites at room temperature, the amplitude of thermal vibration turns out to be twice as large as that of massive cobalt crystals and the numbers of neighbours are found to be equal to those which are calculated for a mixture of h.c.p. and diamond structures. At high temperatures, cobalt crystallites become to be h.c.p. and gradually transform to f.c.c. structure. The amplitude of thermal vibration is 0.15A at 250°C a...
TL;DR: In this article, the chemical shift, spin-lattice relaxation time, and intensity of nuclear magnetic resonance line were measured for ammonium chloride, bromide and iodide in various phases.
Abstract: The chemical shift, spin-lattice relaxation time, and intensity of nuclear magnetic resonance line were measured for ammonium chloride, bromide and iodide in various phases. It was found that the reorientational motion of ammonium ion is the origin of time dependent interaction necessary to relax the nuclear spin orientation. The deformation of the halogen ion core, arising from the interaction with alkali ions, is discussed in connection with the chemical shift and spin-lattice relaxation time. In ordered phase, T 1 in the chloride became much longer than that in phase II, while in the bromide electric quadrupole splitting of NMR line appeared, and the ordering parameter was estimated. From the result of the intensity measurements, the effect of crystal imperfection upon NMR is discussed.
TL;DR: In this article, the temperature dependences of tetragonal-cubic phase transition of Co-Mn manganites are given; this transition is shown to be of the 1st order.
Abstract: The temperature dependences of tetragonal-cubic phase transition of Co–Mn manganites are given; this transition is shown to be of the 1st order. The phase diagram in the usual chemical meaning is shown. The cation distribution of the Co–Mn oxide spinel is measured by Fe–Kα radiation; Mn ions tend to occupy B-site preferentially. The lattice parameters of specimens which were quenched from 1000°C are given. The critical fraction of Mn ions on B-site for the abrupt occurrence of bulk crystal distortion is 60%. The meaning of the thermal hysteresis of electrical resistance and the anomalous peak of differential thermal analysis, appearing at the reduction and oxidation temperature and at the tetragonal-cubic transition temperature, is discussed. The hysteresis and anomalous peak corresponding to the tetragonal-cubic transition are distinct from those corresponding to the reduction and oxidation.
TL;DR: In this paper, the authors studied the properties of CS (NH 2 ) 2 with particular reference to its ferroelectric transitions and found that the hysteresis loop in intermediate phase III is transformed into a double loop with a variation of temperature.
Abstract: The hysteresis loop, the specific heat and the thermal expansion of CS (NH 2 ) 2 have been studied with particular reference to its ferroelectric transitions. The hysteresis loop in intermediate phase III is transformed into a double loop with a variation of temperature. The field dependence of the transition temperature is given by d T c / d E =+ and -0.5 deg. cm/kV for the upper and lower sides of phase III, respectively. Below phase III, a decrease of the critical field is observed by applying a stress on the (100) or (001) face. A new ferroelectric loop is also observed at -102°C with the spontaneous polarization of 2×10 -4 µ coul/cm 2 . The specific heat anomaly is found at -106°C with the latent heat of 6.6±01 cal/mol. In [100] and [001] directions, expansion anomalies are found; a jump of 0.9×10 -3 is observed especially in the [100] direction at -105°C. The results are examined according to the phenomenological theory. The dipole moment of the molecule in the crystal is discussed and a molecular m...