AB-INITIO STUDY OF THE INTERACTION OF RHODIUM WITH DINITROGEN AND CARBON-MONOXIDE

Ab initio computations at the B3LYP/ECP level have been performed on a series of charged and neutral rhodium species containing carbon monox ide and dinitrogen ligands. The computations have been employed to pre dict possible oxidation states of supported Rh for new surface species detected by infrared spectroscopy during the interaction of the metal with CO and N-2 in the presence of ultraviolet radiation. Specificall y, it has been concluded that Rh species containing N-2 ligands giving rise to low-frequency N-N stretching modes most likely contain Rh wit h a -1 oxidation state, the source of electrons being due to photoindu ced electron transfer between supported Rh metal centers in the presen ce of UV irradiation. Although the computations refer to gas-phase Rh species, it is believed that computations, such as those reported here in, can be useful in predicting trends in vibrational frequencies for similar surface species and thus aid in vibrational band assignments f or specific structures.