VIBRATIONAL LEVELS AND FRANCK-CONDON FACTORS OF DIATOMIC-MOLECULES VIA MORSE POTENTIALS IN A BOX

This work deals with two shortcomings in the use of Morse potentials t o describe energy spectra and transitions of diatomic molecules: (1) M orse's well-known ''exact'' solution for purely vibrational states inc ludes the unphysical region - infinity < r < 0 of the internuclear sep aration, and (2) Franck-Condon factors are evaluated in harmonic and a nharmonic approximations to the Morse potentials. The method of confin ing the molecule in a spherical box is developed to obtain (1) purely vibrational energy spectra and eigenvectors of Morse potentials in the physical region 0 less than or equal to r < infinity, and (2) the cor responding Franck-Condon factors without any additional approximations . The method is applied to Li-2, N-2, CN, and CO molecules. (C) 1995 J ohn Wiley & Sons, Inc.