The dipole gradient for isolated C-H stretches 2. Partially deuterated methyl fluoride, methyl chloride and methyl iodide

Article abstract of DOI:10.1016/0022-2860(93)87027-7

The vapour phase infrared contours, at 0.5 cm^-1 resolution, of the C-H stretch fundamental in CHD2F, CHD2Cl and CHD2I have been simulated using anharmonic rigid asymmetric top calculations.The smallest angle between the C-H bond direction and the dipole gradient that reproduces the experimental contour, obtained by rotating the gradient from the C-H bond towards the bisector of the methyl group, was found to be 15 +/- 5 deg in CHD2F, 38 +/- 2 deg in CHD2Cl and 49 +/- 3 deg in CHD2I.Together with the corresponding value for CHD2Br, these results are compared with the polarizability of the halogen atom.