Development of a ReaxFF Force Field for Cu/S/C/H and Reactive MD Simulations of Methyl Thiolate Decomposition on Cu (100)

Jejoon Yeon, Heather L. Adams, Chad E. Junkermeier, Adri C.T. Van Duin, Wilfred T. Tysoe, Ashlie Martini

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

It has been shown that the rate of decomposition of methyl thiolate species on copper is accelerated by sliding on a methyl thiolate covered surface in ultrahigh vacuum at room temperature. The reaction produces small gas-phase hydrocarbons and deposits sulfur on the surface. Here, a new ReaxFF potential was developed to enable investigation of the molecular processes that induce this mechanochemical reaction by using density functional theory calculations to tune force field parameters for the model system. Various processes, including volumetric expansion/compression of CuS, CuS2, and Cu2S unit cells; bond dissociation of Cu-S and valence angle bending of Cu-S-C; the binding energies of SCH3, CH3, and S atoms on a Cu surface; and energy for the decomposition of methyl thiolate molecular species on copper, were used to identify the new ReaxFF parameters. Molecular dynamics simulations of the reactions of adsorbed methyl thiolate species at various temperatures were performed to demonstrate the validity of the new potential and to study the thermal reaction pathways. It was found that reaction is initiated by C-S bond scission, consistent with experiments, and that the resulting methyl species diffuse on the surface and combine to desorb ethane, also as found experimentally.

Original languageEnglish (US)
Pages (from-to)888-896
Number of pages9
JournalJournal of Physical Chemistry B
Volume122
Issue number2
DOIs
StatePublished - Jan 18 2018

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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