An ab initio study on the vibrational and electronic spectra of the molybdenum–sulfur clusters with Mo 2O nS 4− n( n=0–4) core

Abstract

Using the ab initio method, the vibrational and electronic spectra of binuclear molybdenum clusters which contain Mo 2O n S 4− n ( n=0–4) core were investigated. The main absorption bands in the IR spectra of these clusters are assigned and compared with each other, especially for the case of the trans isomers. The electronic spectra were studied by performing the CIS calculations. The ground state and the first excited state of the clusters were discussed by using the natural bond orbital method. It is shown that the band corresponding to the longest wavelength can be assigned to three kinds of transition types. Two transitions, σ(Mo–Mo)→π*(Mo–X t)(X=S,O) and σ(Mo–Mo)→σ*(Mo–Mo), can be seen in most cases.