A four-constant potential function for Se0.79Te0.21 alloy and evaluation of thermodynamic and acoustic properties

New potential function has been developed using cohesive energy, bulk modul us and second order elastic constants (SOECs). Longitudinal, transverse and thermal Gruneisen constants are calculated from the potential function. Fr om the pressure derivatives the band absorption position and third order el astic constants (TOECs) are evaluated and these are used in the calculation of CI. The Bhatia-Singh's equations are used in the computations of longit udinal and transverse phonon frequencies. From the low values of phonon fre quencies, C-11 and C-44 are obtained and these are in excellent agreement w ith experimental values and hence forms a good serf-consistent check.