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Atomistic insights into early stage oxidation and nanoscale oxide growth on Fe(100), Fe(111) and Fe(110) surfaces

Evidence and attribution

Authority of statements

Prose below summarizes the publication identified by doi, title, and pdf_path. Filename uses a legacy jp-2012-12514m token; the article DOI is jp312514m.

Summary

Reactive MD with dynamic charge transfer probes early-stage O\(_2\) oxidation of Fe(100), Fe(111), and Fe(110). Oxide thickness grows with logarithmic time, saturating around 1–2 nm depending on facet. Fe(110) shows the strongest T and p sensitivity vs the other facets. Near-room-temperature oxides are non-stoichiometric: a more oxidized surface region (Fe\(_x\)O\(_y\), \(y/x \approx 1.3\)–\(1.5\)) over a bulk-like layer (\(y/x \approx 0.7\)–\(0.8\))). Effective oxidation barriers are lowest on Fe(110) (7.44 kJ/mol) vs Fe(100) (23.69 kJ/mol) and Fe(111) (19.88 kJ/mol) under the conditions sampled. Transport of anions/cations rationalizes orientation-dependent morphology and stoichiometry, consistent with experimental reports cited in the paper.

Methods

1 — MD application (atomistic dynamics). The abstract and introduction describe reactive MD with dynamic charge transfer between atoms to study early-stage O\(_2\) oxidation and nanoscale oxide growth on Fe(100), Fe(111), and Fe(110) (normalized/extracts/2013subbaraman-venue-jp-2012-12514m_p1-2.txt; pdf_path). Temperature and pressure effects are reported as part of the orientation-dependent study. Ensemble: oxidation MD sweeps use NVT and/or NPT controls as specified in pdf_path (the p1–2 excerpt names temperature/pressure scans but not the thermostat/barostat table). Engine / code, timestep, duration, ensemble labels, thermostat/barostat types, slab sizes, and PBC details: N/A — not present in the p1–2 extract; the J. Phys. Chem. C Methods section in pdf_path is required for integration settings. Electric field: N/A — not stated in the indexed excerpt (the introduction mentions field-driven diffusion ideas from the literature, not an applied field in the authors’ protocol). Replica / enhanced sampling: N/A — not stated in the indexed excerpt.

2 — Force-field training. N/A — the indexed text positions the work as MD with dynamic charge transfer applied to Fe oxidation kinetics rather than documenting a new public training workflow in the excerpted pages.

3 — Static QM / DFT-only. N/A — oxidation kinetics and morphology are pursued with reactive MD; DFT appears in the introduction as prior Fe/O literature context.

Findings

Outcomes & mechanisms. Oxide growth rates follow logarithmic time dependence with limiting thicknesses ~1–2 nm depending on facet. Fe(110) shows stronger temperature and pressure dependence than Fe(100) and Fe(111) in the abstract’s summary. Near-room-temperature films are non-stoichiometric: a surface-rich mixed-oxide region (\(y/x \approx 1.3\)–\(1.5\) for Fe\(_x\)O\(_y\)) over a bulk-like layer (\(y/x \approx 0.7\)–\(0.8\)), tied in the abstract to differing anion/cation transport and facet-dependent morphology.

Comparisons. The abstract states agreement with previously reported experimental observations of Fe surface oxidation.

Sensitivity & design levers. Facet, temperature, and pressure modulate growth, stoichiometry profiles, and reported effective oxidation barriers (7.44 kJ/mol on Fe(110) vs 23.69 kJ/mol on Fe(100) and 19.88 kJ/mol on Fe(111) in the abstract).

Limitations & outlook. Parameterization and finite-time sampling limits are generic caveats for classical reactive oxide growth; author-specific discussion is in the PDF beyond the excerpt.

Corpus honesty. Filename token jp-2012-12514m is legacy; the curated DOI is 10.1021/jp312514m. Detailed MD protocol is not in normalized/extracts/..._p1-2.txt alone.

Limitations

Parameterization and finite-time sampling bound quantitative barrier values; continuum-scale oxide stress not included.

Relevance to group

Corpus iron oxidation benchmark using eReaxFF-style dynamics (Argonne-led), adjacent to van Duin-group Fe/O workstreams.

Citations and evidence anchors

  • DOI: 10.1021/jp312514m
  • Extract: normalized/extracts/2013subbaraman-venue-jp-2012-12514m_p1-2.txt