ABSTRACT
Theoretical investigations show that low-temperature processes should have a number of features related to quantum effects. In the low-temperature regions, both the discrete character of the energy levels and the possibility of tunnel passage of particles become more important. Reactions proceeding at temperatures that are low for most vibrational system degrees of freedom, are denoted as low-temperature reactions. The physical mechanism of the transition is most clearly seen for harmonic intramolecular degrees of freedom and effective oscillators for the polar medium. In the Condon approximation the electron resonance integral should be calculated at the values of the intramolecular coordinates and the inertial polarization of the medium corresponding to the transition configuration. The dependence of the electron resonance integral on the intramolecular nuclear coordinates is due to the corresponding dependence of the electron wave functions. Experimental investigations of the processes of photosynthesis have stimulated development of the theory.
