Combined perturbative-variational investigation of the vibrations of CHBr3 and CDBr3

A full dimensional vibrational treatment of CHBr3 and CDBr3 using Van Vleck perturbation theory followed by a variational calculation is presented. The calculation of a force field, and its adjustment for better match with experiment, is discussed. The computed eigenstates and spectral features are compared to experiment. Changes in intensities of the nu(1) and 2nu(4) bands upon simple alterations of the dipole moment expansion are described. (C) 2004 American Institute of Physics.