Electronic contribution to the pressure dependence of the Bulk Modulus in a jellium approximation

The Murnaghan. equation of state (EOS) for solids is based on the assumption of a bulk modulus (B) linear with pressure. The derivative of B to P at zero pressure (n = partial derivativeB/partial derivativeP I-T) is a key parameter for this EOS. Generally n is considered as a constant mainly due to the lack of reliable information about its thermal dependence. Recently, some of the authors have shown that the Bulk Modulus values at zero pressure can be well explained by considering only the electronic contribution through a non-stabilized jellium. (NS-jellium) model. Here we will show how this approach can be extended to obtain values of n. Comparisons with experimental data show that this electronic contribution only accounts for approximately 30% of the n experimental values.