Effect of hydrogen chemisorption on the photoionization threshold of isolated transition metal clusters
1987; Elsevier BV; Volume: 135; Issue: 3 Linguagem: Inglês
10.1016/0009-2614(87)85146-1
ISSN1873-4448
AutoresM. R. Zakin, D. M. Cox, Robert L. Whetten, D. J. Trevor, A. Kaldor,
Tópico(s)Mass Spectrometry Techniques and Applications
ResumoLarge increases in the photoionization threshold energies of small Vx, NBx, and Fex clusters (x = 3–25) induced by chemisorption of H2 have been observed using photoionization time-of-flight mass spectrometry of a molecular beam. These shifts exhibit a definite dependence both on the number of atoms constituting the bare metal cluster and on the number of chemisorbed hydrogens, and are particularly large (≳ 0.8 eV) for multiple-H2 chemisorption on small clusters. A simple frontier orbital model for the chemisorption process predicts the direction of adsorbate-induced shifts in cluster ionization threshold for both H2 and NH3 as adsorbates.
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