ISOMERISM OF NI CLUSTER ANIONS AND ITS ROLE ON PHOTO-DETACHMENT SPECTROSCOPY

First principles calculations based on density functional theory and t he generalized gradient approximation reveal that a Ni dimer anion can exist in two nearly degenerate forms characterized by different bond lengths and spin multiplicities. Similarly Ni-3(-) exhibits two isomer ic forms-a linear chain and an equilateral triangle but both having th e same quarter spin multiplicity and protected by an energy barrier of about 0.8 eV. The existence of these isomers impacts strongly on the interpretation of the experimental photo-detachment spectra. (C) 1997 Elsevier Science B.V.