Evaluation of Force Constants of Tetrahedral Hydrides from Raman and Infrared Data

The force constants of 4 molecules and 4 ions of the type XH4 belonging to the Td symmetry have been calculated by Wilson's F–G matrix method, using Raman and infrared data. Using a modified Urey-Bradley field, the force constants between nonbonded atoms were calculated separately and substituted in the main equations. Anharmonicity was not taken into account.