Development of a ReaxFF Force Field for Cu/S/C/H and Reactive MD Simulations of Methyl Thiolate Decomposition on Cu(100)
Corpus note
The ingested PDF is a proof; the published article is identified by the ACS DOI in the extract footer.
Summary¶
A ReaxFF reactive force field for Cu/S/C/H was developed and trained against density functional theory (DFT) data so that reactive molecular dynamics can probe methyl thiolate chemistry on copper, including the mechanochemical acceleration of decomposition observed under mild sliding in ultrahigh vacuum. The work reports DFT-driven parametrization (bulk sulfides, adsorption and decomposition paths on Cu(100)) and thermal ReaxFF molecular dynamics of adsorbed methyl thiolates to compare with experiment. Methyl thiolate coverage on Cu(100) is a well-studied surface-science anchor for organosulfur tribochemistry, motivating a single reactive model that spans bulk Cu–S chemistry and adsorbate reaction sequences on the close-packed terrace.
Methods¶
Force-field training (ReaxFF + DFT). A Cu/S/C/H ReaxFF description is optimized using density functional theory (DFT) reference data for CuS, CuS₂, and Cu₂S unit-cell equation-of-state curves, Cu–S bond dissociation, Cu–S–C angle bending, SCH₃/CH₃/S adsorption energies on Cu, and energy profiles along methyl thiolate decomposition pathways on Cu(100)—mirroring the abstract’s training inventory. DFT barriers for thiolate decomposition are noted to agree with experiment in prior work cited by the authors. Parameter optimization follows the manuscript’s ReaxFF fitting workflow (see [[2017jejoon-yeon-j-phys-chem-development-reaxff]] for the version-of-record narrative when pagination differs from this proof PDF).
Molecular dynamics (reactive). Molecular dynamics simulations of CH₃S/methyl thiolate decomposition on Cu(100) at multiple temperatures complement mechanochemical sliding protocols discussed in the article, separating thermal C–S scission from shear-biased pathways under controlled stress/pressure conditions reported in the JPCB Methods. Periodic slab models with explicit atom counts, timestep (fs), thermostat coupling, NVT staging, equilibration/production duration (ps/ns), and any barostat usage should be read from papers/Yeon_CuSCH_JPCB_2017_proof.pdf or the final JPCB layout—this wiki does not duplicate every numerical control from the proof ingest. Electric fields and metadynamics/umbrella enhanced sampling are not highlighted in the excerpted introduction beyond noting parallel replica dynamics as a general rare-event strategy in the literature.
Static QM / DFT. DFT supplies training energies and reaction profiles; it is not the long-time MD engine.
Review scope. N/A — primary research communicated through this proof duplicate slug.
Findings¶
Outcomes and mechanisms. Thermal ReaxFF MD shows methyl thiolate decomposition initiating with C–S bond scission, after which methyl fragments diffuse on Cu(100) and recombine to desorb ethane, matching the experimental picture summarized in the abstract.
Comparisons. Mechanochemical UHV sliding accelerates decomposition relative to purely thermal trajectories at similarly mild interface temperatures, consistent with tribochemical observations that stress can lower effective barriers without large frictional heating.
Sensitivity / design levers. Temperature sweeps in MD bracket reaction propensity for covered surfaces; shear amplitude enters the mechanochemical discussion as the mechanical analogue of pressure/stress in Bell-type models.
Limitations / outlook. Proof PDF pagination may differ from the final JPCB article; rare events may still demand accelerated sampling beyond standard MD lengths.
Corpus honesty. This page tracks papers/Yeon_CuSCH_JPCB_2017_proof.pdf; cite [[2017jejoon-yeon-j-phys-chem-development-reaxff]] when you need version-of-record locators, and pull any missing protocol numerics from the PDF rather than this summary.
Limitations¶
Local proof PDF and abbreviated extract: simulation protocol details (timestep, thermostat, system sizes, run lengths) should be confirmed from the full article or SI when present.
Relevance to group¶
Develops ReaxFF for sulfur–copper tribochemistry and surface decomposition pathways with Adri C. T. van Duin as a coauthor; connects to reactive interface modeling in the broader van Duin ReaxFF line.
Citations and evidence anchors¶
- DOI:
10.1021/acs.jpcb.7b06976(version-of-record citation; confirm page locators from PDF).