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Title: Photo-induced valence change of the sulfur atom in an L-cysteine thin film grown on a silver metal substrate in a saliva-emulated aqueous solution

A thin film of L-cysteine (HSCH{sub 2}CH(NH{sub 2})COOH) is grown on a silver substrate in saliva-emulated aqueous solution. X-ray photoemission spectroscopic measurements have revealed that the sulfur atom shows valence change under IR laser irradiation at 825 nm. The valence change maintains for about a minute at room temperature and more than an hour between 110 and 250 K after stopping the laser irradiation. It is not observed at all at temperatures lower than 110 K. This temperature-dependent behavior indicates that the photo-excited electronic change should be accompanied by a conformational change in the L-cysteine molecule. It is strongly suggested that the reversible valence change of the sulfur atom is applicable to a memory used around room temperature.
Authors:
 [1] ; ; ; ;  [2]
  1. Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan)
  2. Synchrotron Light Application Center, Saga University, 1 Honjo, Saga, Saga 840-8502 (Japan)
Publication Date:
OSTI Identifier:
22398981
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AQUEOUS SOLUTIONS; ATOMS; CONFORMATIONAL CHANGES; CYSTEINE; LASER RADIATION; MOLECULES; PHOTOELECTRON SPECTROSCOPY; PHOTOEMISSION; SALIVA; SILVER; SUBSTRATES; SULFUR; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VALENCE; X RADIATION