Hydrogen-bond mediated transitional adlayer of glycine on Si(111)7 x 7 at room temperature.
The growth of glycine film by thermal evaporation on Si(111)7 x 7 at room temperature has been studied by X-ray photoemission. In contrast to common carboxylic acids, glycine is found to adsorb on Si(111)7 x 7 dissociatively through cleavage of a N-H bond instead of O-H bond. The intricate evolution of the observed N 1s features at 399.1, 401.4, and 402.2 eV with increasing film thickness demonstrates the existence of a transitional adlayer between the first adlayer and the zwitterionic multilayer. This transitional adlayer is estimated to be 1-2 adlayer thick and is characterized by the presence of intermolecular N...HO hydrogen bond. An intramolecular proton transfer mechanism is proposed to account for the adsorption process through the amino group.
Zhang
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WATLab and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Chatterjee
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A
Ebrahimi
M
M
Leung
K T
KT