Coverage dependent desorption kinetics of CO from Rh(111) using time-resolved specular helium scattering

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.461508· OSTI ID:5127291

Peterlinz, K A; Curtiss, T J; Sibener, S J ^[1]

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1. Chicago Univ., IL (United States). Dept. of Chemistry Chicago Univ., IL (United States). James Franck Inst.

Linearized measurements of the coverage dependent desorption rates of CO from Rh(111) were made with a novel three molecular beam apparatus. To measure these isothermal and essentialy isosteric rates we introduce a new {ital kinetic} {ital response} {ital amplifier}, namely time-resolved specular helium scattering, which makes use of the large attenuation cross section that CO has for specular helium scattering. The measurements are made by using one intense and continuous CO beam to establish a specific adsorbate coverage while another low intensity and chopped CO beam is used to weakly modulate the adsorbate density around the selected steady state. The transient helium reflectivity waveforms we measure during the modulated CO scattering contain the desired kinetic information, and are typically one to almost two orders of magnitude more sensitive to the desorption kinetics than are the signals arising from direct detection of desorbing CO. Desorption rates are reported for 0{le}{theta}{sub CO}{le}0.22 and 440 K {le}{ital T}{sub {ital S}}{le}555 K.

• OSTI ID: 5127291
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 95:9; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
BEAMS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COLLISIONS
COVERINGS
DESORPTION
DIFFRACTION
ELEMENTS
FLUIDS
GASES
HELIUM
HIGH TEMPERATURE
ISOTHERMAL PROCESSES
KINETICS
METALS
MOLECULAR BEAMS
MOLECULE COLLISIONS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RARE GASES
RESOLUTION
RHODIUM
SCATTERING
SORPTION
TIME RESOLUTION
TIMING PROPERTIES
TRANSITION ELEMENTS