Rovibrational Hamiltonians for general polyatomic molecules in spherical polar parametrization. II. Nonorthogonal descriptions of internal molecular geometry

A rovibrational kinetic energy operator for a two-vector embedded reference frame is derived for general polyatomic molecules of arbitrary structure. New compact expressions for (T) over cap in terms of angular momentum and l inear momentum vector operators are explicitly given for tri-, tetra-, and pentatomic molecules. The necessary actions for the evaluation of kinetic e nergy matrix elements in a standard rotation-angular basis are summarized. The structure of kinetic energy operators in the body-fixed formulation is explained with the help of Cartesian components of angular momentum and lin ear momentum vector operators. Kinetic energy operators for tetratomic mole cules in a bisector embedded body-fixed formulation and for sequentially bo nded pentatomic molecules are derived to show how to use our general result for diverse coordinate systems. (C) 2000 American Institute of Physics. [S 0021-9606(00)00203-8].