Knowledge Bank

“With a potential function based on the valence force field, approximation, Wilson’s, G-F matrix method was used to determine the force constants of a simplified molecular model of methyl thionitritc $(CH3SNO)$. The derivation of the model’s Lagrangian function in Cartesian coordinates WAS used as a check of the numerical calculations performed with the aid of the G-F matrix method. The model’s normal modes of vibration and their normalized energy distribution among the internal coordinates were calculated; both indicate considerable mixing of two normal coordinates. As a result of the force constants evaluation, the frequency assignments previously given for two stretching vibrations were revised. The calculated force constants are compared to values for similar stretching and bending modes whenever available from the literature. “