The mechanisms leading to desorption of molecular hydrogen from and surfaces have been elucidated and refined by detailed examination of the thermal desorption kinetics with particular emphasis on low and very low coverages. In the case of hydrogen desorption from a lattice-gas model incorporating the interactions that are responsible for pairing and clustering of adsorbed hydrogen atoms has been employed to fit temperature programmed desorption (TPD) peaks resulting from initial coverages between 0.01 and 1.0 monolayer (ML). From analysis of our low coverage data, we find that the pairing and clustering energies are and respectively. A subtle shift of the TPD peak maximum position as the initial coverage increases from 0.2 to 1.0 ML indicates that the pre-exponential factor and activation energy are weakly coverage dependent. We discuss how this is consistent with coupling of a dihydridelike transition state to its neighbors. The rate of molecular hydrogen desorption from is found to be very nearly second order in total hydrogen coverage when the initial coverage is low. This result is consistent with a two site model involving preferential adsorption of hydrogen atoms at rest atom sites rather than adatom sites.
Skip Nav Destination
Article navigation
22 February 1998
Research Article|
February 22 1998
The desorption of molecular hydrogen from Si(100)-2×1 and Si(111)-7×7 surfaces at low coverages
Michael C. Flowers;
Michael C. Flowers
Chemistry Department, University of Southampton, Southampton, SO17 1BJ, United Kingdom
Search for other works by this author on:
Neville B. H. Jonathan;
Neville B. H. Jonathan
Chemistry Department, University of Southampton, Southampton, SO17 1BJ, United Kingdom
Search for other works by this author on:
Alan Morris;
Alan Morris
Chemistry Department, University of Southampton, Southampton, SO17 1BJ, United Kingdom
Search for other works by this author on:
Steven Wright
Steven Wright
Chemistry Department, University of Southampton, Southampton, SO17 1BJ, United Kingdom
Search for other works by this author on:
J. Chem. Phys. 108, 3342–3352 (1998)
Article history
Received:
July 11 1997
Accepted:
November 12 1997
Citation
Michael C. Flowers, Neville B. H. Jonathan, Alan Morris, Steven Wright; The desorption of molecular hydrogen from Si(100)-2×1 and Si(111)-7×7 surfaces at low coverages. J. Chem. Phys. 22 February 1998; 108 (8): 3342–3352. https://doi.org/10.1063/1.475733
Download citation file:
Pay-Per-View Access
$40.00
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
DeePMD-kit v2: A software package for deep potential models
Jinzhe Zeng, Duo Zhang, et al.
CREST—A program for the exploration of low-energy molecular chemical space
Philipp Pracht, Stefan Grimme, et al.
Dielectric profile at the Pt(111)/water interface
Jia-Xin Zhu, Jun Cheng, et al.
Related Content
Tert-butyl nitrite surface photochemistry: The transition from submonolayer to multilayer behavior
J. Chem. Phys. (January 1998)
Abstraction of D adsorbed on Pt(111) surfaces with gaseous H atoms
J. Chem. Phys. (February 1998)
Chemical diffusivity and wave propagation in surface reactions: Lattice-gas model mimicking CO-oxidation with high CO-mobility
J. Chem. Phys. (January 1998)
Continuum elastic theory of adsorbate vibrational relaxation
J. Chem. Phys. (January 1998)
Extended series expansions for random sequential adsorption
J. Chem. Phys. (February 1998)