摘要：

The interaction of carbon monoxide with 3d metal dimers (scandium through zinc) has been examined using six different exchange-correlation density functionals. Results are compared to the relevant experimental values and to other theoretical investigations when available, and the overall agreement has been obtained. The BP86 functional gives calculated C-O stretching vibrational frequencies much closer to the experimental values than the B3P86, B3LYP, mPW1PW91, and PBE1PBE functionals, and furthermore, replacing the correlation part by the Lee-Yang-Parr correlation functional yields essentially the same results. It is generally found that on going from left to right across the 3d metal series, the preference for geometrical configuration is from side-on-bonded mode to bridging, and then to terminal, whereas Ni(2)CO adopts bridging mode. Particularly, the present computation reveals a significant tendency toward four-electron donor carbonyl groups with metal-oxygen bonds with the early transition metals scandium and titanium. The C-O stretching vibrational frequencies in the ground states of M(2)CO (M=Sc to Zn) increase generally from the left to the right side of the Periodic Table. The binding energies exhibit an overall decrease trend. These general trends in the interaction of carbon monoxide with 3d metal dimers mirror the main features of CO adsorption on transition metal surfaces.

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