Surface chemistry of alanine on Cu{111}: Adsorption geometry and temperature dependence

Baldanza, S., Cornish, A., Nicklin, R. E. J., Zheleva, Z. V. and Held, G. (2014) Surface chemistry of alanine on Cu{111}: Adsorption geometry and temperature dependence. Surface Science, 629. pp. 114-122. ISSN 0039-6028 doi: 10.1016/j.susc.2014.04.016

Abstract/Summary

Adsorption of l-alanine on the Cu{111} single crystal surface was investigated as a model system for interactions between small chiral modifier molecules and close-packed metal surfaces. Synchrotron-based X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy are used to determine the chemical state, bond coordination and out-of-plane orientation of the molecule on the surface. Alanine adsorbs in its anionic form at room temperature, whilst at low temperature the overlayer consists of anionic and zwitterionic molecules. NEXAFS spectra exhibit a strong angular dependence of the π ⁎ resonance associated with the carboxylate group, which allows determining the tilt angle of this group with respect to the surface plane (48° ± 2°) at room temperature. Low-energy electron diffraction (LEED) shows a p(2√13x2√13)R13° superstructure with only one domain, which breaks the mirror symmetry of the substrate and, thus, induces global chirality to the surface. Temperature-programmed XPS (TP-XPS) and temperature-programmed desorption (TPD) experiments indicate that the zwitterionic form converts into the anionic species (alaninate) at 293 K. The latter desorbs/decomposes between 435 K and 445 K.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/37851
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Uncontrolled Keywords	Chiral surfaces; Alanine; Copper; Photoelectron spectroscopy; NEXAFS; TPD
Publisher	Elsevier
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