Thermodynamic functions of germane isotopologues AGeH4 (A = 70, 72, 73, 74, 76) calculated from high-resolution IR spectra

Abstract

Standard thermodynamic functions of germane isotopologues ⁷⁰GeH₄, ⁷²GeH₄, ⁷³GeH₄, ⁷⁴GeH₄, and ⁷⁶GeH₄ are calculated in “harmonic oscillator – rigid rotator” and “anharmonic oscillator – oscillating non-rigid rotator” approximations and by the direct summation of the experimental energy values. To found the values of thermodynamic functions in the 200–700 K temperature range, approximation coefficients are determined by regression analysis. The isotope effect influence on the values of the standard isobaric heat capacity, entropy, enthalpy of heating, and the reduced isobaric-isothermal potential of germane is established. Limiting requirements for the accuracy of determining the spectral parameters for detecting the influence of the isotope effect on the thermodynamic functions and interatomic distances in the germane molecule are formulated.