Mean Amplitudes of Vibration and Thermodynamic Functions of the Difluorides of Oxygen and Silicon

The developments in the vibrational assignment and molecular parameters of the difluorides of oxygen and silicon have been reported. The theory of mean‐square amplitude matrices has been applied to the bent symmetrical XY2 molecular model. Four valence force constants have been evaluated on the basis of Wilson's group theoretical method for these two molecules. Numerical values of the ten mean‐square amplitude quantities have been given at the temperatures T=O and T=298°K. The corresponding mean amplitudes of vibration for O – F, Si – F and F – F distances have also been given at these temperatures. The observed fundamental frequencies have been utilized for the calculation of molar thermodynamic functions assuming a rigid rotator, harmonic oscillator approximation for the temperature range from 100° to 1700°K.