Energy transfer and photochemistry on a metal surface: Mo(CO)/sub 6/ on Rh(100)

Journal Article · Mon May 01 00:00:00 EDT 1989 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.576020· OSTI ID:6338360

Germer, T A; Ho, W

The occurrence of photoinduced reactions on solid surfaces depends on the relative rates between the excited-state decomposition and the energy transfer to the surface. In this study, the photodecomposition of Mo(CO)/sub 6/ on Rh(100) at 90 K by 325-nm UV irradiation has been studied as a function of coverage and surface preparation using thermal desorption spectroscopy, electron energy-loss spectroscopy, and photoinduced desorption spectroscopy. It is found that Mo(CO)/sub 6/ adsorbs dissociatively on Rh(100) into carbonyl fragments and CO in the first monolayer and molecularly in multilayers. Photoinduced desorption of CO is observed for the multilayers adsorbed onto the dissociated first layer via a nonthermal electronic excitation of adsorbed metal carbonyls. The presence of the metal surface prevents complete decarbonylation as in the gas phase; deexcitation of electronically excited carbonyls is not sufficiently fast to quench all the observed photochemistry. It is also found that Mo(CO)/sub 6/ adsorbs molecularly on a presaturated CO ordered overlayer on Rh(100) and undergoes photodissociation to a greater degree than on the dissociated and disordered surface of carbonyl fragments. The ordered CO layer effectively screens the interaction between the molecular carbonyls and the Rh(100) layer surface.

• Research Organization: Laboratory of Atomic and Solid State Physics and Materials Science Center, Cornell University, Ithaca, New York 14853-2501
• OSTI ID: 6338360
• Journal Information: J. Vac. Sci. Technol., A; (United States), Vol. 7:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
MOLYBDENUM
DECOMPOSITION
RHENIUM
SURFACE PROPERTIES
CARBON OXIDES
DESORPTION
ELECTRON SPECTROSCOPY
ENERGY-LOSS SPECTROSCOPY
LOW TEMPERATURE
PHOTOCHEMICAL REACTIONS
ULTRAHIGH VACUUM
CARBON COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
METALS
OXIDES
OXYGEN COMPOUNDS
SPECTROSCOPY
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies