Anharmonicity in isochoric heat capacity for Mg2SiO4

Abstract

An expression has been formulated to find the values of volume dependence of isochoric heat capacity (C_V). It is employed on Mg₂SiO₄. It has been found that isochoric heat capacity decreases strongly with increase in compression or pressure. Anharmonicity on C_V for solid under present investigation has been seen above 1500 K under low compression. However, at low temperature, for both low and high compression, and at high temperature under high compression, quasi-harmonic effects are visible. Under high compression, beyond 1200 K the C_V increases slowly monotonically with the temperature. It attains peak value at/around Debye temperature. With increasing compression, the curves become steeper. At high temperatures, C_V under high compressions depart from that estimated by the Dulong-Petit theory.