title: Photoemission and photoabsorption spectroscopy of glycyl-glycine in the gas phase.
abstract: The high-resolution outer and inner valence band (VB) spectra, as well as core level X-ray photoemission (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectra at the carbon, nitrogen, and oxygen K-edges of glycyl-glycine in the gas phase have been measured, and the results interpreted by means of ab initio calculations. By comparison with our previous glycine spectra, the features characteristic of the peptide bond in the carbon, nitrogen, and oxygen XPS and NEXAFS spectra of glycyl-glycine have been identified and assigned. The K-edge NEXAFS spectra at all edges were found to be in reasonable agreement with published electron energy loss spectra, but showed more prominent structure due to the higher resolution. Effects on the nitrogen K-edge NEXAFS spectrum of glycyl-glycine due to intramolecular hydrogen bonding were observed. The N(NH(2)) 1s --> pi*(CN) resonance shifts to 0.6 eV lower energy, due to internal hydrogen bonding between the NH(2) and NH groups.
authors.affiliation: Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza, Trieste, Italy. vitaliy.feyer@elettra.trieste.it
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Feyer
authors.forename: Oksana
authors.initials: O
authors.lastname: Plekan
authors.forename: Robert
authors.initials: R
authors.lastname: Richter
authors.forename: Marcello
authors.initials: M
authors.lastname: Coreno
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Prince
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Carravetta
mesh_terms: D004579:Electron Transport; D005998:Glycine / Q000737:chemistry*; D006033:Glycylglycine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D044367:Phase Transition; D010777:Photochemistry; D056951:Photoelectron Spectroscopy; D011487:Protein Conformation; D056928:X-Ray Absorption Spectroscopy
chemical_list: D006033:Glycylglycine; D005998:Glycine