The structures and vibrational frequencies for eclipsed and staggered conformers of CF2HCH3, CF3CFH2, C2F5H, and C2F6 have been calculated by using B3LYP and MP2 ab initio methods. A reassignment of the experimental IR spectra of CF3CFH2 and C2F6 is suggested. Relative electronic energies are determined with a number of basis sets. Electron correlation is included by means of Møller-Plesset perturbation methods up to the fourth order. Scaled vibrational frequencies are used to account for zero-point energy and thermal contributions to electronic energies. Temperature dependence of the rotational barriers is studied at 20 K intervals from 0 to 300 K.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry