Nitromethane was adsorbed onto four alkali halide films: KBr, NaCl, NaBr, and KCl. Photolysis took place at various temperatures using a mercury lamp. This photolysis produced several photoproducts which were identified through analysis of FTIR spectra. An unpredicted change in the two CH3 stretch peaks, occurring at 3079 and 3044 cm-1, was detected and attributed to the increasing temperature. As the temperature increased, the peaks became broader and began to overlap. These peaks were indicative of two conformations of the methyl group. The change observed in the peaks was caused by an increased ability of the methyl group to rotate about the C-N bond from one conformation to the other as a result of the increasing temperature. The energy of activation for the methyl rotation for each of the peaks and on each of the salt films was calculated. The Ea was higher for the 3079 cm-1 peak than for the 3044 cm-1 peak, indicating that the conformation represented by the 3079 cm-1 peak is favored over the other conformation.