Theoretical study on the photostimulated desorption of CO from a Pt surface

H. Nakatsuji, H. Morita, Hiromi Nakai, Y. Murata, K. Fukutani

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Photostimulated desorptions (PSD's) of CO, CO+, and CO- from a Pt surface are studied theoretically using Pt2-CO model cluster including image force correction. Calculations are performed by the single excitation configuration interaction and the symmetry adapted cluster (SAC)/SAC-CI methods. The PSD's of the ground state CO occur as the Menzel-Gomer-Redhead (MGR) process and those of CO+ (n cation) and excited (n→π*) CO* through the modified MGR process in which the upper repulsive potential curves are nonadiabatic; the process proceeds through a sequence of nonadiabatic transitions between the similar pertinent states embedded in the metal excited bands. The excited states as the desorption channels are characterized by the excitations from the Pt-CO bonding orbitals to the antibonding MO's: metal-adsorbate chemical bond cleavage by photons which leads to a repulsive potential is essential for the PSD. The electrostatic image force interaction plays only a minor role and the present result does not support the Antoniewicz model. The calculated excitation-energy thresholds for the CO, CO+, and CO* desorptions are 1.6∼2.6, 11.3, and 11.3-12.7 eV, respectively, which explains the energy thresholds and the fluence dependencies of the incident laser in the PSD experiments. On the other hand, the PSD giving CO- would occur with the energy range of 6.2-8.2 eV, one to two photon energy of the 193 nm (6.4 eV) laser. Since the upper nonadiabatic potential curves have shallow minima, in this case, the lifetime of the CO- species would be larger than those of the CO+ and CO* species. The present study clarifies the electronic structures of the desorbed CO+, CO-, and CO* species, which have not been identified experimentally.

Original languageEnglish
Pages (from-to)714-726
Number of pages13
JournalJournal of Chemical Physics
Volume104
Issue number2
Publication statusPublished - 1996
Externally publishedYes

Fingerprint

Carbon Monoxide
Desorption
desorption
excitation
thresholds
energy
photons
symmetry
curves
chemical bonds
metals
configuration interaction
lasers
cleavage
fluence
electrostatics
electronic structure
cations
orbitals
life (durability)

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Nakatsuji, H., Morita, H., Nakai, H., Murata, Y., & Fukutani, K. (1996). Theoretical study on the photostimulated desorption of CO from a Pt surface. Journal of Chemical Physics, 104(2), 714-726.

Theoretical study on the photostimulated desorption of CO from a Pt surface. / Nakatsuji, H.; Morita, H.; Nakai, Hiromi; Murata, Y.; Fukutani, K.

In: Journal of Chemical Physics, Vol. 104, No. 2, 1996, p. 714-726.

Research output: Contribution to journalArticle

Nakatsuji, H, Morita, H, Nakai, H, Murata, Y & Fukutani, K 1996, 'Theoretical study on the photostimulated desorption of CO from a Pt surface', Journal of Chemical Physics, vol. 104, no. 2, pp. 714-726.
Nakatsuji, H. ; Morita, H. ; Nakai, Hiromi ; Murata, Y. ; Fukutani, K. / Theoretical study on the photostimulated desorption of CO from a Pt surface. In: Journal of Chemical Physics. 1996 ; Vol. 104, No. 2. pp. 714-726.
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