Calculation of thermodynamic functions of halogen derivatives of silane and germane

Abstract

Molar heat capacity, absolute entropy, relative enthalpy and relative Gibbs energy were calculated for all halogen derivatives of silane and germane. The calculation was performed for the ideal gas state at atmospheric pressure in the temperature range 100 to 1 500 K in the usual rigid rotator - harmonic oscillator approximation. In the case of molecules where the necessary experimental values of fundamental vibrational frequencies were missing, the calculation was performed using the predicted frequencies. On the basis of the values of molar heat capacities obtained in both these ways, a critical examination of the influence of the inaccuracy of the predicted vibration frequencies on the accuracy of calculated ideal gas thermodynamic functions was made.