Photoelectron Spectra and Geometric Structures of Small Niobium Cluster Anions

Abstract

Photoelectron spectroscopy measurements and density functional theory calculations are combined to determine structures of Nb 2 n (n 3 8) clusters. A detailed comparison between observed and calculated electronic binding energies shows that the clusters have low-symmetry compact 3D structures and the lowest possible total spin, except for the three-and five-ato clusters which are in triplet states. We fin evidence for the coexistence of two isomers of Nb 2 8 under some experimental conditions. This approach shows great promise for structural characterization of small clusters.

Comment on “Concerning the applicability of density functional methods to atomic and molecular negative ions” [J. Chem. Phys. 105, 862 (1996)]

“…Previous and contemporary work ͑e.g., Häberlen et al 10 on icosahedral Au 55 EA's and Kietzmann et al 11 on EA's for small Nb clusters͒ as well as GS's suggests that for lowcharge, relatively large molecular anions, the spurious selfrepulsion can be spread out over a large-enough volume that reasonable estimates of EA's ͑or at least, of trends͒ can be obtained. The issue is whether self-repulsion pushes the anion HOMO up enough that the incorrect asymptotic shape of the approximate potential affects the orbital significantly.…”

On the Electronic and Structural Properties of Tri-Niobium Oxide Clusters Nb3On− (n = 3−8): Photoelectron Spectroscopy and Density Functional Calculations

“…13 19 Using single photon ionization at 26.5 eV for M m O n (M ) V, Nb, Ta), Dong et al identified the general form (MO 2 ) 0,1 (M 2 O 5 ) n (n ) 1-4) as the most abundant neutral clusters. 20 Sambrano et al investigated the geometric, thermodynamic, and electronic properties of Nb m O n 0/+ (m ) 1-3; n ) 2-5, 7, 8) clusters using DFT calculations and suggested that the Nb 3 O n 0/+ (n ) 7, 8) clusters possess chain structures.…”

The far-infrared spectra of neutral and cationic niobium clusters: Nb5∕+ to Nb9∕+

“…Partly because of their relative ease of production and the favorable isotopic distribution, niobium clusters have been intensively investigated experimentally and this has been followed by extensive theoretical studies. Experimental studies include single and multiphoton ionizations, [13][14][15][16] as well as photoelectron spectroscopy [17][18][19][20] and the measurements of the bond dissociation energies. 21,22 Optical absorption spectra of neutral niobium clusters have been measured by means of photodissociation of their complexes with rare-gas atoms [23][24][25] and this technique is also used here for obtaining the vibrational spectra.…”