Desorption Kinetics of Methanol from Al2O3(0001) Studied Using Temperature-Programmed Desorption and Isothermal Desorption

Autor:	S. Y. Nishimura, N. J. Tro, R. F. Gibbons
Rok vydání:	1998
Předmět:	Chemistry Thermal desorption spectroscopy Analytical chemistry Lower temperature Desorption kinetics Isothermal process Surfaces Coatings and Films chemistry.chemical_compound Desorption Monolayer Materials Chemistry Methanol Physical and Theoretical Chemistry Saturation (chemistry)
Zdroj:	The Journal of Physical Chemistry B. 102:6831-6834
ISSN:	1520-5207 1520-6106
Popis:	Temperature-programmed desorption (TPD) and isothermal desorption were used to investigate the desorption of methanol from Al2O3(0001) in ultrahigh vacuum. At low coverages, TPD traces for methanol displayed one broad peak that was attributed to monolayer desorption. A second, multilayer peak was observed at a lower temperature as the coverage was increased. The multilayer peak appeared at coverages well below the saturation coverage of the monolayer peak, implying that the multilayer was forming before the monolayer was completely full. Isothermal desorption studies were performed in the multilayer regime as a function of coverage and temperature. The coverage-dependent studies showed that multilayer desorption was of order n = 0.53 ± 0.12. The temperature-dependent studies showed that the multilayer activation barrier for desorption was 11.1 ± 0.5 kcal/mol with an n = 0.53 order preexponential of 3.1 × 1024 s-1. The approximately half-order desorption from the multilayer is interpreted in terms of a str...
Databáze:	OpenAIRE
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