PREDICTING LANTHANIDE CLUSTER PROPERTIES - A COMPARISON WITH THE OBSERVED OPTICAL-SPECTRA OF HO-2

Ab initio pseudopotential calculations for Ho and Ho, have been carrie d out in order to support an assignment of the bands observed in UV-vi sible spectra of matrix isolated holmium species. SCF, MCSCF and confi guration interaction (CI) procedures have been used with quasirelativi stic pseudopotentials to compute the ground and excited state energies of Ho and Ho-2, together with the dipole transition moments. For Ho-2 , using a Q = 11 pseudopotential (describing the holmium atom in the 4 f(10)6s(2)5d(1) electronic state), two transitions from the ground sta te sigma(g)(2) sigma(u)(2) pi(u)(2) to the states with principal excit ations sigma(u) --> pi(g) and pi(u) --> sigma(g) are predicted at 499 and 524 nm. These two lines, with predicted close intensities, correl ate nicely with the observed features at 498/504 and 558/563 nm in the spectrum of matrix-isolated Ho-2. (C) 1997 Elsevier Science B.V.