Anharmonicity in isochoric heat capacity for Mg₂SiO₄

Abstract

An expression has been formulated to find the values of volume dependence of isochoric heat capacity (<em>C_V</em>). It is employed on Mg₂SiO₄. It has been found that isochoric heat capacity decreases strongly with increase in compression or pressure. Anharmonicity on <em>C_V </em>&nbsp;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 <em>C_V </em>increases slowly monotonically with the temperature. It attains peak value at/around Debye temperature. With increasing compression, the curves become steeper. At high temperatures, <em>C_V </em>&nbsp;under high compressions depart from that estimated by the Dulong-Petit theory.