PERMANENT DIPOLE-MOMENTS OF METHANE-TYPE MOLECULES - CALCULATION OF THE DELTA-J=0 MATRIX-ELEMENTS IN THE I=1 VIBRATIONAL-STATE

We examined permanent dipole moments (PDMs) of methane-type molecules induced by molecular internal motions which are expanded in terms of t he vibrational coordinate operator q, total angular momentum operator J, and vibrational angular momentum operator 1. The qq-, JJ-, Jl-, and II-type quadratic terms of these operators contribute to the producti on of PDMs. The Delta J = 0 matrix elements of the four PDMs are calcu lated for the first excited state of the triply degenerate vibrational mode; a portion are numerically given in a table for the J less than or equal to 6 levels. We have also compared them with the PDM represen ted by the rotational angular momentum operator R = J - 1 and discusse d an application of the present calculations to the upsilon(3) = 2 sta te of methane. (C) 1997 Academic Press.