Quantum theory of molecular rearrangements

A universal approach to description of quantum dynamics of nonrigid molecules and molecular complexes is outlined. The method includes reconstruction of the potential energy surface using data of quantum-chemical calculations of the geometry and eigenfrequencies for the ground and transition states followed by solution of the multidimensional dynamical problem with the semiclassical approximation. The approach is based on the path integral technique and can be used for calculations of frequencies of interconfigurational tunneling transitions in the ground and lowest excited stares of molecules with several stable configurations and for determination of decay probabilities for the same states of metastable systems.