Effect of hydrogen chemisorption on the photoionization threshold of isolated transition metal clusters

✍ Scribed by M.R. Zakin; D.M. Cox; R.L. Whetten; D.J. Trevor; A. Kaldor

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 521 KB
• Volume: 135
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(87)85146-1

✦ Synopsis

Large increases in the photoionization threshold energies ofsmail V, N&, and Fe, clusters (~~3-25) mdueed by cbemisorption of H2 have been observed using photoionization time-of-flight mass spectrometry of a molecular beam. These shifis exhibit a definite dependence both on the number of atoms constituting the bare metal cluster and on the number of cbemisorbed hydrogens, and are particularly large ( ~~0.8 eV) for mnltipie-H, 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 Hz and NH3 as adsorbates.