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Electron Stimulation of Internal Torsion of a Surface-Mounted Molecular Rotor
ACS Nano (2010)
  • Weihua Wang, Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China
  • Xingqiang Shi, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
  • Mochen Jin, Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China
  • C. Minot, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
  • M.A. Van Hove, Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China
  • Jean-Paul Collin, Institut de Chimie, Université Louis Pasteur-CNRS/UMR 7177, 4, rue Blaise Pascal 67070 Strasbourg, France
  • Nian Lin, Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China
Abstract
A molecular rotor which includes a central rotator group was investigated by scanning tunneling microscopy at 4.9 K as it was grafted on a Cu(111) surface via its two terminal stand groups. Sub-molecular resolution topographs revealed alternating molecular conformations which we attribute to distinct angular orientations of the rotator, and which are locally stable states according to density functional theory calculations. Time-resolved tunneling current spectra manifested that the rotator undergoes torsional motions around the molecular long axis as stimulated by tunneling electrons in one-electron processes and obtained an excitation energy threshold of 355 meV. Calculations identified an intrinsic axial vibration mode of the rotator group at 370 meV, which we propose to be the channel for effectively converting the tunneling electron energy into the mechanical energy of the intra-molecular torsion.
Keywords
  • Molecular rotor,
  • electron excitation,
  • scanning tunneling,
  • microscopy,
  • density functional theory calculation
Disciplines
Publication Date
2010
DOI
10.1021/nn101330c
Citation Information
Weihua Wang, Xingqiang Shi, Mochen Jin, C. Minot, et al.. "Electron Stimulation of Internal Torsion of a Surface-Mounted Molecular Rotor" ACS Nano Vol. 4 Iss. 8 (2010) p. 4929 - 4935 ISSN: 1936086X
Available at: http://works.bepress.com/mavanhove/98/