A study on the GVFF of CHF 3, CH 2F 2, and CH 3F

Abstract

The complete GVFF of CHF 3, CH 2F 2, and CH 3F has been calculated from self-consistent-field ab initio energies, using a 4–31 G basis set. The larger part of the interaction force constants is close to those of the best available force fields from experimental data. Only one interaction term in CH 3F and the interaction force constants of the A 1 species in CH 2F 2 differ appreciably from the experimental ones. Using constraints from the ab initio studies we have improved the GVFF of CH 3F and CH 2F 2. It is shown that all comparable stretch-stretch interaction terms are of the same order of magnitude in the three molecules. The sign of all stretch/bend force constants are in accordance with those predicted by the hybrid orbital force field.