Evaluation of the potential function of liquid germanium from experimental structure factors and computation of elastic constants and phonon frequencies

Abstract

Rao-Joarder's equation for the determination of potential function is used to derive the latter. The computed potential function of liquid Ge shows an inflection in the positive region and a negative minimum. The inflection is attributed to the first nearest-neighbour distance and the negative minimum to the second nearest-neighbour distance. The present computed potential function is found to be similar to that obtained by different methods. The derived potential function along with the measured values of g(r) is used in the evaluation of longitudinal and transverse phonon frequencies through Takeno and Goda's equations. The low-k values of phonon frequencies are found to be nearly linear with k. From the slope of these frequencies the elastic constants are calculated. Schofield's equations are also used in the calculation of elastic constants. The values obtained by different methods are found to be interconsistent. The potential function is utilised in the evaluation of the characteristic frequency of the atoms in the liquid. The computed value is compared with that obtained from low temperature heat capacities and average frequencies obtained by different methods. They are found to be fairly interconsistent.