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Interaction of gas phase atomic hydrogen with Pt(111): Direct evidence for the formation of bulk hyd
Employing hot tungsten filament to thermal dissociate molecular hydrogen, we generated gas phase atomic hydrogen under ultra-high vacuum (UHV) conditions and investigated its interaction with Pt(111) surface. Thermal desorption spectroscopy (TDS) results demonstrate that adsorption of molecular hydrogen on Pt(111) forms surface Had species whereas adsorption of atomic hydrogen forms not only surface Had species but also bulk Had species. Bulk Had species is more thermal-unstable than surface Had species on Pt(111), suggesting that bulk Had species is more energetic. This kind of weakly- adsorbed bulk Had species might be the active hydrogen species in the Pt-catalyzed hydrogenation reactions....
2020-09-15 12:28:59浏览：51
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A Possible Pumping Mechanism for Interstellar Class Ⅱ107 GHz Methanol Masers
It is recognized that the interstellar methanol-107GHz masers and OH-4.765 GHz masers towards Class Ⅱ sources are associated with each other and coexist towards ultracompact HII regions. Therefore we suggest a new pumping mechanism - methanol masers without population inversion. It can explain the formation of 107 GHz methanol masers, with the 4.765 GHz OH masers acting as a driving coherent microwave field. It is argued that this mechanism is compatible with the astronomical conditions....
2020-07-08 21:52:19浏览：70
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