Spectroscopic studies of the jet-cooled nickel dimer

Abstract

We report the first gas-phase electronic spectrum of nickel dimer. Ni2 is produced by laser vaporization of metallic nickel in the throat of a supersonic nozzle. Using resonant two photon ionization, bands previously observed in inert matrices and attributed to Ni2 are conspicuous in their absence. Further to the red, an abrupt onset of complicated spectral structure indicates rapid predissociation above 16 680 cm−1. We argue that this represents the true dissociation limit, and places D0=2.068±0.01 eV. A congested pattern of spectral features from 6000 to 9000 Å confirms theoretical predictions of a large number of low-lying electronic states in nickel dimer. Rotationally resolved bands near 8500 Å are indicative of a ΔΩ=+1 transition, with Ω″=4, Ω′=5. Rotational analysis of these bands yields a bond length of 2.200±0.007 Å for the ground state of Ni2, which must be of either 1Γg or 3Γu electronic symmetry species. Both the long bond length of 2.20 Å and the high value of Ω″ are in agreement with theoretical predictions, and confirm that no substantial 3d participation contributes to the chemical bonding of Ni2.

A theoretical study of the effects of transition metal dopants on the adsorption and dissociation of hydrogen on nickel clusters

“…To determine the physicochemical properties of clusters, the ground state geometry of the clusters must be obtained. Equilibrium geometries of pure Ni n ( n = 2–5) clusters were optimized and found to be in good agreement with the literature . For the bimetallic clusters, all possible geometries were attempted.…”

Cobalt clusters (Con, n⩽6) and their anions

“…For PBE, the septet state is the first and the triplet state is the second exited states which are 0.87 eV and 0.99 eV higher in energy than the quintet state. The experimental bond length of the neighboring dimers Fe 2 and Ni 2 are 1.87 Å [39] and 2.155 Å [40], respectively. Our calculated values of 2.13 Å (BLYP) and 2.10 Å (PBE) for Co 2 are slightly less than Ni 2 dimer experimental bond length and in between the values obtained from Pauling radius [31] and Badger's Rule [33].…”

Electronic transitions of palladium dimer

“…[36][37][38][39][40][41][42][43] Extensive investigations on Ni 2 and Pt 2 have also been reported both experimentally and theoretically. 31,[44][45][46][47][48][49][50][51][52] For the transition metals, it is generally recognized that the size of the nd and (n+1)s orbitals change as one moves across the periodic table from left to right: the nd orbitals contract more heavily than the (n+1)s orbital. Therefore, d orbitals in the late transition metals are less available for chemical bonding.…”