ReaxFF potential functions: supporting information (hydrocarbon oxidation manuscript)
Evidence and attribution¶
Authority of statements
Prose sections below describe the supporting-information document identified by pdf_path. They are not new primary claims by this wiki.
Equation numbering and full algebraic details are in the PDF.
Summary¶
This document lists the general ReaxFF potential-function definitions accompanying the same hydrocarbon-oxidation manuscript as the CHO parameter file. It states that the current ReaxFF code evaluates all energy contributions listed, regardless of system composition, and explains naming: parameters without direct physical meaning are named after the partial energy term in which they appear (e.g., valence-angle parameters), while quantities such as torsional barriers use conventional symbols (V1, V2, V3). The extract covers the total system energy decomposition, bond order from interatomic distance (sigma, pi, pipi contributions), and overcoordination definitions used to correct bond orders—including a lone-pair-aware overcoordination for atoms such as oxygen and nitrogen.
Methods¶
The supplement gives the general ReaxFF potential-function definitions in equation form for the same hydrocarbon-oxidation manuscript as the CHO parameter file. It states that the current ReaxFF implementation evaluates every energy contribution listed regardless of system composition, and it explains parameter naming: coefficients without direct physical meaning are named after the partial energy term in which they appear (for example valence-angle parameters), while familiar symbols such as torsional barriers \(V_1\), \(V_2\), \(V_3\) are retained where appropriate. The documented terms include the overall system energy decomposition (Coulomb, van der Waals, bond, hydrogen bond, conjugation, torsion, triple and overcoordination/undercoordination, valence, penalty, lone pair, and bond-order corrections as in Equation (1) of the PDF), bond order from interatomic distance via sigma, pi, and double-pi contributions (Equation (2)), uncorrected overcoordination (Equation (3a)), a lone-pair-aware overcoordination for atoms such as oxygen and nitrogen (Equation (3b)), and the bond-order correction scheme (Equations (4a–f) in the typeset PDF).
MD application (not reported)¶
This supplement defines energy expressions for use in molecular dynamics engines; it does not archive a specific trajectory. N/A — MD code; N/A — atom counts; N/A — PBC; N/A — NVE/NVT/NPT run script; N/A — timestep; N/A — trajectory length (no ps/ns production segment documented here); N/A — equilibration MD schedule in this PDF; N/A — thermostat; N/A — barostat; N/A — MD temperature; N/A — MD pressure; N/A — electric field; N/A — enhanced sampling.
Force-field training (scope boundary)¶
Parent FF / elements: ReaxFF functional form paired with the C/H/O combustion parameterization line. QM / DFT training data, reaction sets, optimizer, and validation tables: N/A in this PDF—read the peer-reviewed hydrocarbon oxidation article and other CHO supplements for DFT reference data and optimization details. This file’s role is documentation of terms that enter the parameter fit performed elsewhere.
Findings¶
The supplement defines the same general ReaxFF energy decomposition (Equation (1)), distance-derived bond orders (Equation (2)), overcoordination and lone-pair-aware \(\Delta'_{\mathrm{boc}}\) corrections (Equations (3a–b), (4a–f)) used with the CHO combustion parameter file. Bond orders combine \(\sigma\), \(\pi\), and double-\(\pi\) contributions; lone-pair-bearing atoms can rearrange bonding without a full spurious overcoordination penalty. Together with the numeric parameter listing, it specifies the functional form a compatible engine must implement for the parent hydrocarbon-oxidation chemistry. Limitations / outlook: N/A — no application benchmarks are reported in this methods PDF alone—consult the parent article. Corpus honesty: equation text in normalized/extracts/2006chenoweth-venue-microsoft-word_p1-2.txt is a fragment; the typeset pdf_path is authoritative.
Limitations¶
- This is methods documentation for implementers; validation and application results are in the main article and application studies.
- PDF text extraction fragments some equation formatting; the typeset PDF is authoritative.
Relevance to group¶
Adri C. T. van Duin is a named co-author on the parent manuscript; this supplement documents the functional form underlying multiple ReaxFF parameterizations in the group’s toolchain.
Citations and evidence anchors¶
- PDF:
papers/CHO_supplements/ReaxFF_CHO_potential_functions.pdf. - Extract:
normalized/extracts/2006chenoweth-venue-microsoft-word_p1-2.txt.