Interactions between Chemisorbed Species:H2andN2on (100) Tungsten
作者:
John T. Yates,
Theodore E. Madey,
期刊:
Journal of Vacuum Science and Technology
(AIP Available online 1971)
卷期:
Volume 8,
issue 1
页码: 63-68
ISSN:0022-5355
年代: 1971
DOI:10.1116/1.1316357
出版商: American Vacuum Society
数据来源: AIP
摘要:
The interactions between hydrogen and nitrogen adsorbed species on a (100) tungsten crystal have been investigated by flash desorption methods. When the crystal covered with a monolayer of hydrogen is exposed to gaseousN2, the nitrogen slowly replaces the two chemisorbed hydrogen β states by means of a slight lowering of the hydrogen desorption energy. This displacement process occurs via slow thermal desorption of hydrogen in the presence of gaseousN2when the surface temperature is ≳300 K no such replacement is observed at 273 K. Coverage measurements indicate that there is a stoichiometric ratio between N atoms adsorbed and H atoms displaced from the crystal at ∼300 K. Although virtually no hydrogen will adsorb on the nitrogen-covered surface at 300 K, several weakly bound hydrogen states are populated at 100 K on this surface. No chemical difference between theβ1andβ2hydrogen species was detected, suggesting that both states originate from adsorbed atoms.
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