Infrared absorption intensities of methylene fluoride

Abstract

Absolute i.r. band intensifies of gaseous CH₂F₂, and CD₂F₂, have been measured with the aid of the pressure broadening technique to determine the dipole moment derivatives with respect to a bond length or a valence angle. Among several sets of converged values of parameter in the least squares calculation, the most reliable one has been chosen by comparing with the calculated results through the CNDO/2 and INDO methods. The determined values of a_CH and a_CF are −0.73 ± 0.14 and −4.23 ± 0.84 D/Å, respectively. The angles between those parameters and the symmetry axis of the molecule are 67.5 ± 11.O° for a_CH and 73.9 ±11.1° for a_CF. When compared with the parameter values of other fluorinated methanes reported in our previous paper, these results can be considered quite reasonable.