ИСТИНА

One of the goals of molecular spectroscopy consists in solution of a rovibrational problem. At the first glance, the solution of this problem can readily be obtained by variational quantum mechanical method. But in reality, quantum mechanical method is restricted. First, the computational cost of such quantum calculations is still too high, so that high precision calculations are available for small molecules only. Second, quantum calculations give numerical results only but don't explain a structure of rotational spectra. To gain a better understanding of a nature of rotational spectra we use classical mechanics. Dynamical equations of a solid body are generalized to real molecules, i.e., with regard to the interaction between the total rotation of a molecule and intermolecular motion. In the context of this classical approach the model of the soft body is proposed.