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Large scale computational chemistry modeling of the oxidation of highly oriented pyrolytic graphite (galley PDF)

Evidence and attribution

Authority of statements

This note registers a galley/proof PDF for the same JPCA article summarized on 2013poovathingal-venue-jp3125999. Scientific content should be taken from the version-of-record page unless you explicitly need this file’s line breaks or figures.

Summary

Same study as 2013poovathingal-venue-jp3125999: ReaxFF molecular dynamics of hyperthermal atomic oxygen (5 eV) oxidizing HOPG, predicting etch-pit evolution, product distributions (O\(_2\) > CO\(_2\) > CO), and pathway activation energies (about 0.30 / 0.52 / 0.67 eV for O\(_2\), CO\(_2\), CO channels in the analysis presented). This wiki entry tracks the galley PDF bytes ingested in the corpus; narrative science should match the version-of-record page, while this file remains useful for provenance when comparing figure placement or pagination against proofs.

Methods

This slug tracks the galley/proof bytes at papers/Poovathingal_Srinivasan_etal_HOPG_oxidation_JPCA_2013_galley.pdf. The scientific protocol is the same article as 2013poovathingal-venue-jp3125999; use that page’s pdf_path for pagination-stable Methods tables and figures when possible.

1 — MD application (same study; galley PDF provenance)

  • Engine / code: Large-scale molecular dynamics with ReaxFF implemented in LAMMPS (same article Methods as 2013poovathingal-venue-jp3125999; read papers/Poovathingal_Srinivasan_etal_HOPG_oxidation_JPCA_2013.pdf when galley pdf_path text is hard to extract reliably).
  • System size & composition: HOPG is modeled as a bulk hexagonal graphite slab with ABAB stacking, a frozen bottom layer, Langevin-controlled substrate layers to mimic bulk dissipation, and an oxygen atom beam initialized 15 Å above the surface with 5 eV normal kinetic energy for sequential impacts (VOR Methods). Isolated small models in the same article discuss defect energetics on the order of 100–3000 atoms (VOR PDF text).
  • Boundaries / periodicity: Three-dimensional periodic boundary conditions in LAMMPS supercells as described in the VOR Methods (paired PDF).
  • Ensemble: The 1 ps high-energy O-atom collision integrations use velocity-Verlet with 0.25 fs timesteps and explicitly checked energy conservation in the Methods text (paired PDF), i.e., effectively microcanonical dynamics for those collision legs, while selected substrate layers use Langevin thermostatting to represent bulk coupling (paired PDF).
  • Timestep: 0.25 fs with velocity-Verlet integration (VOR Methods).
  • Duration / stages: The Methods describe 1 ps integration for initial high-energy collisions under low-pressure experimental separation assumptions, with longer sequential-collision campaigns described later in the article (paired PDF).
  • Thermostat: Langevin thermostat on selected substrate layers (paired PDF figure/methods caption as referenced in the article).
  • Barostat: N/A — not the primary control mode for the quoted collision protocol (paired PDF).
  • Temperature: Large-scale sequential-collision runs sample surface temperatures of 300, 600, 1000, and 1500 K (broader than the 298–573 K experimental window, which the authors note is too narrow for MD statistics) (papers/Poovathingal_Srinivasan_etal_HOPG_oxidation_JPCA_2013.pdf, Results discussion excerpt).
  • Pressure: N/A — beam-energy-controlled oxidation scenario (abstract framing).
  • Electric field: N/A.
  • Replica / enhanced sampling: N/A.

2 — Force-field training

N/A — application/validation of C/H/O ReaxFF with QM benchmark checks as summarized in the shared abstract (see 2013poovathingal-venue-jp3125999).

Findings

  • Outcomes & mechanisms: Same abstract-level results as 2013poovathingal-venue-jp3125999: oxygen precursor, etch pits, edge-localized carbon removal, O\(_2\) > CO\(_2\) > CO product ranking, and pathway E_a values ~0.30 / 0.52 / 0.67 eV for the dominant channels discussed there.
  • Comparisons: Versus molecular-beam experiments and ab initio-derived energetics checks as in the shared article narrative.
  • Sensitivity / design levers: Beam energy (5 eV) and sequential-impact large-cell protocol are the main knobs highlighted in the abstract/intro shared across PDF variants.
  • Limitations & outlook: Galley/proof formatting can differ in line breaks/figure placement; for citation-ready locators and SI pointers, prefer version-of-record ingest 2013poovathingal-venue-jp3125999.
  • Corpus honesty: This wiki entry is intentionally duplicate PDF provenance; do not treat this file as an independent scientific source beyond what matches the VOR page.

Limitations

Proof/galley formatting; prefer the non-galley PDF for citation-ready pagination when available. Hyperthermal atomic oxygen beams in experiment can include energy spread and angular distributions that differ from the idealized single-energy impacts used for comparability in the MD protocol. Surface contaminants and multilayer graphene wrinkles in HOPG samples can steer oxidation localization compared to ideal basal planes. Etch-pit morphologies in experiment should be compared using the same length scales and time windows reported for MD analysis in the version-of-record article.

Relevance to group

Duplicate ingest for archival provenance; primary narrative lives with 2013poovathingal-venue-jp3125999.

Citations and evidence anchors

  • DOI: 10.1021/jp3125999
  • Extract: normalized/extracts/2013poovathingal-venue-research_p1-2.txt