On the level clustering in the spectra of the non-rigid spherical top molecules

Abstract

The qualitative theory of level clustering in the rotational spectrum of the cubic symmetry molecules at large angular momenta is built on the basis of approximate methods of solution of three-term recurrent relations (TRR). The discrete quasi-classical approximation and the approximation of the TRR by a second-order differential equation are considered. The analytical expressions for cluster energy and splitting due to tunneling are obtained.