Yu. A. Freiman

Many-body interactions and high-pressure equations of state in rare-gas solids

The T=0K equations of state (EOS) of rare-gas solids (RGS) (He, Ne, Ar, Kr, and Xe) are calculated in the experimentally studied ranges of pressures with the two- and three-body interatomic forces taken into account. Solid-state corrections to the pure two-body Aziz et al. potentials included the long-range Axilrod–Teller three-body interaction and short-range three-body exchange interaction. The energy-scale and length-scale parameters of the latter were taken as adjustable parameters of theory. The calculated T=0K EOS for all RGS are in excellent agreement with experiment in the whole range of pressures. The calculated EOS for Ar, Kr, and Xe exhibit inflection points where the isothermal bulk moduli have non-physical maxima, indicating that account of only three-body forces becomes insufficient. These points lie at pressures 250, 200, and 175GPa (volume compressions of approximately 4.8, 4.1, and 3.6) for Ar, Kr, and Xe, respectively. No such points were found in the calculated EOS of He and Ne. The rel...

Anharmonic effects in librational motion of N2-type crystals

The dynamics of librational motion in N2-type crystals (α-N2, α-CO, N2O, CO2) is treated by taking into account both anharmonic and correlation effects. The method used is similar to Tyablikovs method in the theory of magnetism. The main thermodynamic characteristics of the librational subsystem are calculated: the order parameter, rms librational angle, librational mode frequencies and corresponding Grüneisen parameters, librational heat capacity, and internal and free energies. The librational isotope effects for α-14N2 and α-15N2 are considered. An explanation of the anomalous isotope effects in the heat capacity is proposed. A theory of the phase transition into the orientationally disordered state is developed.

Broken Symmetry Phase Transition in Solid HD: Quantum Behavior at Very High Pressures

The broken symmetry phase (BSP) transition in solid HD has been shown to be an example of quantum orientational melting. Anomalous features observed for the transition are a consequence of the symmetry properties of the system, namely, the fact that in HD all rotational states and transitions between them are allowed, in contrast to the behavior of the homonuclear H2 and D2.

Equation of state and Raman-activeE2glattice phonon in phases I, II, and III of solid hydrogen and deuterium

We present results of lattice dynamics calculations of the

Lattice distortion in hcp rare gas solids

P-V

Molecular rotation in p-H2 and o-D2 in phase I under pressure

equation of state and the pressure dependence of the Raman-active

Self-Consistent Theory of Lattice Distortion in Solid p-H2, o-D2 and HD

E_{2g}

Reentrant Orientational Phase Transitions and Critical Points at Quantum Orientational Melting

lattice phonon for

Magnetic properties of solid oxygen under pressure (Review Article)

p-

Sound velocities in solid hydrogen under pressure

H