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 difl uoromethane in order to find a suitable path to accurate ideal gas heat cap acities. Now, these calculations are extended to all fluorochloro-derivativ es of methane. Reliable experimental heat capacity data reveal that the com bination of quantum mechanics and statistical thermodynamics facilitates a prediction of ideal gas heat capacities with an accuracy of +/-1% and bette r. This is very close to the range of accuracy, which is observed or the be st experimental zero pressure heat capacity data from different sources of the literature.