VIBRATION-TORSION-ROTATION POLARIZABILITY TENSOR OPERATOR FOR A MOLECULE WITH AN INTERNAL ROTOR

The sequential contact transformation technique is applied to the vibr ation-torsion-rotation polarizability tensor operator for a molecule c ontaining a threefold symmetric internal rotor. Detailed discussions a bout various types of polarizability tensor operators end correspondin g vibration-torsion-rotation transitions are presented. The formalism of the transformed polarizability tensor operator makes it possible to analyze various high-order vibration-torsion-rotation interactions an d their effects as well as to determine the intensities of transitions between vibration-torsion-rotation states within the Raman spectrum o f the molecule. As an example, the transition matrix elements of the t ransformed polarizability tensor operators are discussed for CH3OH-lik e molecules. (C) 1998 American Institute of Physics. [S0021-9606(98)00 703-X].