A study of elastic constants and photon eigenvalues of amorphous As₂S₃

Abstract

Both the longitudinal, ω_L(k), and the transverse, ω_T(k), of phonon frequencies of As₂S₃ are found to be nearly linear up to the near maximum. The first peak in ω_L(k) is found to be near 1.7 Å^-1 while, in S(k), the major peak is found to occur at 3.5 Å^-1 which is nearly twice the first peak maximum value in ω_L(k). It is an important result, but this result is difficult to interpret. The γ_g^L and γ_g^T values, as calculated from Schofield's and Bhatia-Singh's parameter, are found to be in good agreement with that of Brugger and Fritz. The band absorption position calculated from elastic constants and Bhatia Singh's parameters are in good agreement with experiments. The third order elastic constants calculated through Siren's non-linear parameter agree well with literature values. The calculated value of the pressure derivative of the bulk modulus from compressibility equation of state is found to be in satisfactory agreement with experiments.