Adsorption Studies with a Bakeable Quartz Automatic Recording Ultramicrobalance
A torsional quartz balance designed and fabricated by the Rodder Instrument Company, has been successfully integrated into a bakeable ultrahigh-vacuum system. Working sensibilities of 0.01 µg are obtained routinely and dynamic response is rapid enough to permit adsorption studies on clean metal surfaces with a sticking coefficient near unity. Adsorption of carbon monoxide on platinum foils has been measured and found to agree with irreversible Langmuir kinetics with a sticking coefficient of 0.38. This agrees with measurements made by flash filament desorption. Adsorption of ethylene is more complicated, but the results are consistent with more detailed mechanistic studies performed in this laboratory on 〈111〉 single-crystal platinum.
KeywordsPlatinum Foil Average Cluster Size Sticking Coefficient Ionization Gauge Solubility Isotherm
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