Vibrational Frequencies and Ideal Gas Heat Capacities of Fluorochloro-Derivatives of Methane as Calculated from Quantum Mechanical Methods

In a previous paper various quantum mechanical methods were applied to difluoromethane in order to find a suitable path to accurate ideal gas heat capacities. Now, these calculations are extended to all fluorochloro-derivatives of methane. Reliable experimental heat capacity data reveal that the combina- tion of quantum mechanics and statistical thermodynamics facilitates a predic- tion of ideal gas heat capacities with an accuracy of \10 and better. This is very close to the range of accuracy, which is observed for the best experimental zero pressure heat capacity data from different sources of the literature.