CALCULATED RJ2-TYPE EFFECTIVE DIPOLE-MOMENT PARAMETERS FOR FUNDAMENTAL BANDS OF TETRAHEDRAL XY4 MOLECULES

Formulas in terms of basic molecular constants are presented for effective dipole moment parameters which are responsible for second-order corrections to the line intensities of fundamental bands of tetrahedral XY4 molecules. Two cases have been considered. In the first case all bands were considered as separate bands. In the second case the ν2 and ν4 bands were considered as interacting bands. The influence of effective Hamiltonian transformations on effective dipole moment parameters has been studied. Numerical calculations of effective dipole moment parameters for the ν2 and ν4 bands of 12CH4 have been performed. There is reasonable agreement between calculated and fitted values of effective dipole moment parameters when these bands are considered separately and there is no such agreement when interactions between these bands are considered in explicit form. The possible reasons for the discrepancies are discussed. © 1991.