Surface chemistry of ultrathin films of histidine on gold as probed by high-resolution synchrotron photoemission.
Procedures for the vacuum deposition of thin histidine films on polycrystalline Au(111) and their characterization with high-resolution synchrotron-radiation-based photoelectron spectroscopy are reported. The chemical form of histidine (anionic vs zwitterionic) and the nature of its interactions with the substrate (strong ionic-covalent vs weak van der Waals bonding) in mono- and multilayer films are analyzed. It is shown that water adsorption on a pre-prepared histidine film at 100 K results in protonation of histidine molecules and partial formation of hydroxyl anions. These chemical effects are carefully differentiated from spectral changes associated with radiation damage of the histidine films.
Zubavichus
Yan
Y
Angewandte Physikalische Chemie, University of Heidelberg, INF 253, 69120 Heidelberg, Germany. yan.zubavichus@urz.uni-heidelberg.de
Zharnikov
Michael
M
Yang
Yongjie
Y
Fuchs
Oliver
O
Heske
Clemens
C
Umbach
Eberhard
E
Tzvetkov
George
G
Netzer
Falko P
FP
Grunze
Michael
M
D000327:Adsorption; D006046:Gold / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry* / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D015394:Molecular Structure; D017785:Photons; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties; D017356:Synchrotrons; D014867:Water / Q000737:chemistry; D014965:X-Rays
D008567:Membranes, Artificial; D014867:Water; D006639:Histidine; D006046:Gold