Temperature and Pressure Effects on Lattice Properties of Pure C60 Solid

A simple model based on atom-atom potential has been used to calculate various bulk, structural and thermodynamic properties of pure C_{60} solid by including implicit anharmonicity. The pressure and temperature dependent properties such as bulk modulus, lattice and orientational structure, thermal expansion, phonon frequency shift, Gruneisen parameters, heat capacity and entropy have been calculated and compared with available data. Though results for some of these properties have been calculated earlier, using improved potential models to suit C60 solid, this paper ascertains the extent of validity of a potential used successfully in the past explaining the observed properties of aromatic hydrocarbons. The same potential used without modification does reproduce, barring orientational absolute minimum configuration, broadly, all the other calculated properties to similar degree of accuracy. It thus provides a platform to include additional terms for interpreting properties of doped C60 solids and polymerized C60 systems.

V.K. Jindal, K.Dharamvir, Sarbpreet Singh · 1999