Effect of mode interaction on spectroscopic parameters of molecular vibrations with combination frequencies

An equation has been obtained for excited vibrations with combination frequencies by modifying the equation for the normal vibrations of the molecules, using the direct product operation and its properties for the eigenvalues and eigenvectors of the cofactor matrices within matrix perturbation theory. From the solution of the equation, the elements of the vibrational mode tensor are determined, for which formulas are written (in terms of projectors of the matrix of the dynamic coefficients) that take into account their changes for excited vibrations. Using these formulas makes it possible to study the effect of perturbations on the change in the intramolecular and spectroscopic parameters of combination vibrations of the molecules. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 421–425, July–August, 2006.