MAGNETIC CIRCULAR-DICHROISM OF MATRIX-ISOLATED MO ATOMS - SPIN-ORBIT-COUPLING AND JAHN-TELLER ACTIVITY

The magnetic circular dichroism and absorption spectra of molybdenum a toms isolated in Ar, Kr, and Xe matrices have been measured. A method of moments analysis has been applied to the spectral results and the z 7P excited state spin-orbit (SO) coupling constants determined. In Ar the SO constant is 126 cm-1, greater than the ps value of 101 cm-1, w hile in Kr and Xe it is smaller, 84.5 and 57.5 cm-1, respectively. The se results compare favorably with the values predicted by a recent the ory of SO coupling for metals in matrices. It is further shown that ma trix-enhanced second-order SO coupling, which was found to be importan t in Cr in the rare gas matrices, is negligible in the present systems . In addition, the method of moments was used to determine the contrib utions of the noncubic rare ps cage vibrational modes to the observed bandwidths, an approach which has been used previously to identify exc ited state Jahn-Teller activity. It is shown that Mo atoms in all thre e gas matrices exhibit a strong Jahn-Teller effect on the z 7P state.