Calculation of vibronic spectra of polyatomic molecules in the franck—condon and herzberg—teller approximations: Part I. Methods for calculating matrix elements

A number of methods, both accurate and approximate, have been developed to calculate the integrals arising in the theory of vibronic spectra of polyatomic molecules. These methods make it possible to calculate the vibrational structure of the electron spectra of polyatomic molecules in the most general approximations (one-electron, adiabatic) without imposing any particular restrictions (neglect of the Dushinsky effect, temperature distribution of molecules, etc.). A comparison is made of the suggested methods, the approximate methods are analyzed for limits of accuracy, and the optimal fields of application are pointed out.