Inorganic Chemistry, Vol.50, No.19, 9219-9229, 2011
Electronic Structure and Bonding in Heteronuclear Dimers of V, Cr, Mo, and W: a CASSCF/CASPT2 Study
Heteronuclear dimers like CrMo, CrW, MoW, VCr, VMo, VW, and their anions have been investigated by means of multiconfigurational quantum chemistry methods, using the complete active space self-consistent field followed by second-order perturbation theory, CASSCF/CASPT2. We explored in great detail several spectroscopic properties such as bond length, potential energy surfaces, dissociation energies, ionization potentials, electron affinities, low-lying excited states, vibrational frequencies, and dipole moments. All proposed dimers show ground states. with a pronounced multireference character. The group VI heterodimers have a (1)Sigma(+) ground state, while the mixed group V-group VI heterodimers show a (2)Delta ground state. Among all dimers, only VCr presents a potential energy profile with a deep minimum in the d-d region and a shelf-like potential in the s-s region. All the remaining dimers show only the short-range minimum. The largest effective bond is obtained for the MoW, with a value of 5.2, that is, a weak sextuple bond. Most of the obtained results are valuable tools to drive future experimental investigations.