Ni2 revisited: Reassignment of the ground electronic state

Abstract

Resonant two-photon ionization spectroscopy was used to study jet-cooled Ni2 produced by pulsed laser ablation of a nickel target in the throat of a supersonic nozzle using argon as the carrier gas. Spectral regions previously investigated using helium as the carrier gas were reinvestigated, and the improved cooling achieved was found to suppress transitions arising from an Ω=4 state that had been thought to be the ground state. Seven new vibronic progressions were assigned, with spectroscopic constants determined for the excited states. The predissociation threshold in Ni2 was reinvestigated, and a revised value for the binding energy is given as D○0(Ni2)=2.042±0.002 eV. The ionization energy of Ni2 was found to be 7.430±0.025 eV, and from this result and the revised bond dissociation energy of the neutral, the binding energy of the cation was calculated to be D○0(Ni+2)=2.245±0.025 eV. Similarly, D○0(Ni−2)=1.812±0.014 eV is obtained using D○0(Ni2) and the electron affinities of Ni and Ni2. Twenty bands were rotationally resolved, all originating from a lower state of Ω″=0+g or 0−u which we argue is the true ground state, in agreement with ligand field and ab initio theoretical studies. The rotational analysis also yielded a ground state bond length of 2.1545±0.0004 Å for 58Ni2.

First-principles calculations on the role of Ni-doping in Cu clusters: From geometric and electronic structures to chemical activities towards CO2

“…The calculated data of 2.221 (1.125), 2.213 (1.215) and 2.111 (1.563) Å (eV) agree fairly well with experiments [29,[33][34][35][36][37], respectively. We note that though the Ni-Cu bond length is slightly smaller than that of the Cu-Cu, the average binding energy of the NiCu dimer is clearly larger than that of the Cu 2 dimer, thus the Ni atom prefers a high-coordination site so as to enhance the total binding energy.…”

Electronic and geometric structures of Co2Cn− and V2Cn−: Initial growth mechanisms of late and early 3d transition-metal carbide clusters

“…The bond lengths of M 2 are summarized in Table I. [33][34][35][36] The calculations agree fairly well with the experiments with a difference of only 0.04 Å at most. One exception was Mn 2 , where the present calculation predicted the spin multiplicity of 11, while the singlet ground state is reported for matrix-isolated Mn 2 by the electron-spin-resonance experiment.…”

Databases for Transition Element Bonding: Metal−Metal Bond Energies and Bond Lengths and Their Use To Test Hybrid, Hybrid Meta, and Meta Density Functionals and Generalized Gradient Approximations

“…The bond energy for Ni 2 comes from Pinegar et al 22 and not the earlier value that was determined by Morse et al 23 and reported by Lombardi and Davis. 20 The equilibrium bond lengths (r e ) for Cr 2 , Cu 2 , Mo 2 , and V 2 also come from Lombardi and Davis.…”