Molecular beam experiments on the sticking and accommodation of molecular hydrogen on a low-temperature substrate
Molecular beams, microcalorimetry, and mass spectrometry are used to study the physisorption kinetics of H/sub 2/ and D/sub 2/ molecules on a low temperature substrate. The energy transferred to the surface of a liquid-helium cooled bolometer by an incident room temperature beam of H/sub 2/ and D/sub 2/, and the number density of the scattered molecules are measured. The sticking coefficient S and the accommodation coefficient ..cap alpha.. are obtained as a function of N, the surface coverage by H/sub 2/ or D/sub 2/. For both isotopes, S and ..cap alpha.. depend strongly on N. S(H/sub 2/) changes from 0.07 +- 0.05 to 0.80 +- 0.02 and ..cap alpha..(H/sub 2/) from 0.31 +- 0.07 to 0.97 +- 0.01 as N increases from approx. =0 to 3 x 10/sup 15/ molecule cm/sup -2/. In the same coverage range, S(D/sub 2/) changes from 0.25 +- 0.05 to 0.92 +- 0.04 and ..cap alpha..(D/sub 2/) from 0.3 +- 0.1 to 0.975 +- 0.025.
- Research Organization:
- Guelph-Waterloo Center for Graduate Work in Chemistry and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- OSTI ID:
- 5319637
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 72:10
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
DEUTERIUM
ADSORPTION
HYDROGEN
COLLISIONS
KINETICS
MOLECULAR BEAMS
RECOMBINATION
SUBSTRATES
ULTRALOW TEMPERATURE
BEAMS
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
SORPTION
STABLE ISOTOPES
640301* - Atomic
Molecular & Chemical Physics- Beams & their Reactions