Molecular Orbital Calculations on the Interaction of PF3 and CO with Ni and Cu Atoms

Abstract

Abstract The interaction of Ni and Cu atoms with PF3 and CO ligands was investigated by means of ab initio MO calculations. Coupling occurs mainly through the HOMO (8a1 for PF3 and 5 a for CO) levels with the metal 4s and 3dz2 orbitals, if the 3dn-1 4s1 electronic configuration of the metal atom is considered. The estimated M-PF3 bond lengths are 2.0 Å for Ni and 2.5 Å for Cu. Calculations with Ni(3d10) revealed for PF3 a more pronounced electron transfer to the ligand than for CO. The results are consistent with experimental UPS data for mononuclear complexes as well as corresponding adsorption systems. In particular, split-off d-states observed in UPS data for adsorbed PF3 are attributed to the pronounced lowering of the 3d-orbital energy of the metal atom upon interaction with this electropositive ligand.