Vibrational relaxation of carbon dioxide (101) and carbon monoxide (v = 2) during gas--surface collisions
The probability for deactivation of CO(v = 2) and CO/sub 2/(101) on collision with polycrystalline silver surfaces has been measured. The deactivation probability for CO(v = 2) was found to decrease from 0.33 at 300 K to 0.20 at 440 K, while the deactivation probability for CO/sub 2/ (101) was found to decrease from 0.72 at 300 K to 0.37 at 440 K. Since no population was observed in the CO(v = 1) and CO/sub 2/ (001) intermediate levels, it appears that each deactivation proceeds completely to produce the vibrational ground level. The magnitudes for the deactivation probabilities and the temperature dependencies indicate that a dominant mechanism for relaxation involves trapping and subsequent deactivation by one or more of several mechanisms, including electron--hole pair formation, vibration-to-rotation energy transfer, or perhaps even transfer of energy to the surface phonons. The experiments were performed in a UHV chamber by using a tunable infrared laser source to excite gas-phase molecules vibrationally before their collision with the surface and by measuring the population of vibrationally excited molecules through their time-resolved infrared fluorescence.
- Research Organization:
- Department of Chemistry, Cornell University, Ithaca, New York 14853
- OSTI ID:
- 5999344
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 82:3; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
HIGH TEMPERATURE
MEDIUM TEMPERATURE
METALS
MOLECULE COLLISIONS
OXIDES
OXYGEN COMPOUNDS
RELAXATION
SILVER
SURFACES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
VIBRATIONAL STATES