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Title: Dissociation pathways of a single dimethyl disulfide on Cu(111): Reaction induced by simultaneous excitation of two vibrational modes

We present a novel reaction mechanism for a single adsorbed molecule that proceeds via simultaneous excitation of two different vibrational modes excited by inelastic tunneling electrons from a scanning tunneling microscope. Specifically, we analyze the dissociation of a single dimethyl disulfide (DMDS, (CH{sub 3}S){sub 2}) molecule on Cu(111) by using a versatile theoretical method, which permits us to simulate reaction rates as a function of sample bias voltage. The reaction is induced by the excitation of C-H stretch and S-S stretch modes by a two-electron process at low positive bias voltages. However, at increased voltages, the dissociation becomes a single-electron process that excites a combination mode of these stretches, where excitation of the C-H stretch is the energy source and excitation of the S-S stretch mode enhances the anharmonic coupling rate. A much smaller dissociation yield (few orders of magnitude) at negative bias voltages is understood in terms of the projected density of states of a single DMDS on Cu(111), which reflects resonant excitation through the molecular orbitals.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ; ; ;  [5]
  1. Catalysis Research Center, Hokkaido University, Sapporo 001-0021 (Japan)
  2. (Japan)
  3. Surface and Interface Science Laboratory, RIKEN, Wako 351-0198 (Japan)
  4. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044 (Japan)
  5. Department of Advanced Materials Science, The University of Tokyo, Kashiwa 277-8561 (Japan)
Publication Date:
OSTI Identifier:
22304426
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COUPLING; DISSOCIATION; DISULFIDES; ELECTRIC POTENTIAL; ELECTRONS; ENERGY SOURCES; EXCITATION; MOLECULES; REACTION KINETICS; SCANNING TUNNELING MICROSCOPY; TUNNEL EFFECT