On the method and results of calculation of vibrational tetrahedral sub-level energies and resonance interactions in vibrational spectra of high symmetry molecules: CH4 and GeH4 as an application of the XY4 (Td) molecule.

We report here the analytical description of one of the important problems in the study of XY4 (Td) molecules, namely, description of vibrational tetrahedral sub-level structures and resonance interactions caused by the high symmetry of a molecule. The results obtained are applied to description of the vibrational energy spectrum of the CH4 and GeH4 molecules.