Cohesive and thermal properties of transition metal diborides

We have investigated the cohesive and thermal properties of the transition metal diborides (CrB2, HfB2, NbB2 and TaB2) using a rigid ion model (RIM), which consists the long-range Coulomb, the short-range repulsive and the van der Waals interactions. The investigation includes the computation of the cohesive energy phi, Restrahalen frequency (nu(O)), Debye temperature (Theta(D)) and Gruneisen parameter (gamma) of the transition metal diborides. Furthermore we have computed the specific heat at constant volume as a function of temperature. The specific heat curves computed from this model are, generally, in good agreement with their available experimental data for CrB2 and NbB2. (C) 2009 Elsevier B.V. All rights reserved.