Homogeneous Electron Research Articles

Solvent effect on electron transfer reactions: Comparison of homogeneous and heterogeneous electron exchange between V3+ and V2+ in water + t-butanol mixtures

Solvent effect on electron transfer reactions: Comparison of homogeneous and heterogeneous electron exchange between V3+ and V2+ in water + t-butanol mixtures

Origin of Anomalies and Thermodynamic Aspects in Invar Alloys

The effect of the forced magnetostriction on various thermodynamic properties of Invar alloys is examined. The temperature variations of the thermal expansion coefficient and bulk modulus defined at constant magnetization and the concentration dependences of this bulk modulus and the high-field susceptibility at constant volume are shown to be normal. There is an enhancement due to the magnetovolume coupling in the high-field susceptibility, compressibility and forced magnetostriction. The various anomalies are attributed to the large magnetovolume coupling in Fe–Ni Invar alloys. It is seen that Fe–Pt alloys are rather normal at low temperature. The magnetovolume coupling term is calculated in a simple itinerant electron model for fcc Fe–Ni alloys. To explain the large magnetovolume coupling in Fe–Ni alloys, the homogeneous itinerant electron model is not sufficient and a magnetic inhomogeneity with different atomic volumes will explain this discrepancy.

Propagation of waves in warm plasma with anisotropic pressure

The effect of the thermal electron pressure on the propagation characteristics of arbitrarily directed waves travelling in a homogeneous warm electron magneto-plasma is dealt with in this paper. It is noted that, in general, thermal pressure does not affect the propagation characteristics of those waves which are electro-magnetic in nature but it excites another wave known as the electron plasma mode. In the case of the isotropic pressure, only ono electron plasma mode propagates in all possible directions. But when the thermal electron pressure is considered to be anisotropic, two electron plasma waves propagate in any arbitrary direction other than the directions along and perpendicular to the external magnetic field, in which directions only one electron plasma wave propagates. The phase velocities of these waves are discussed in detail for several particular cases.

Many-body enhancement of the spin susceptibility of metals

I t is well known (i) that the electron-electron interactions lead to an enhancement of the paramagnetie susceptibility of a metal over the Pauli free-electron susceptibility. This metallic property is not affected by the electron-phonon interaction and, therefore, offers a better comparison between theory and experiment than the heat capacity. Very recently D v P R ~ and GELDART (2) have reviewed the evidence. A discrepancy seems to exist between the theoretical values determined (3.5) within the framework of the Landau theory of Fermi liquids and the experimental evidence. In this letter we report values of the enhancement factor determined in the framework of the Landau theory on the basis of the t reatment of electron correlations developed by SisGwi, SJbLX~DER, TOSI and LAND (6). This differs from the previous approaches in that short-range Coulomb correlations are taken approximately into account. The results are compatible with the experimental evidence and in good agreement with the alternative theoretical approaches of HAMANN and OVEI~gA~SER (7) and DUPREE and GELDART (2), which also include approximately the Coulomb correlations. The Landau interaction between two quasi-particles in a homogeneous and isotropic electron liquid, defined as the second functional derivative of the ground-state energy with respect to the quasi-particle occupation numbers, depends on the spins of the

Nonlinear generation of transverse fluctuations from longitudinal fluctuations in an infinite stable plasma

The stationary spectrum of transverse electric field fluctuations, generated by nonlinear interaction of longitudinal waves, in a homogeneous and isotropic electron plasma of infinite extension and in the absence of external fields, is calculated. Only the lowest-order nonlinear effect, yielding transverse waves with frequencies somewhat above 2ωd and, respectively, small compared toωd, is considered, including, however, nonresonant modes. An estimate of the order of magnitude of the effect is given for equilibrium fluctuations, which may serve as a starting point for evaluating its importance in cases where enhanced longitudinal fluctuations are present.