openWFN

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openWFN 0.7 is a reproducible command-line and Python workbench for Gaussian formatted-checkpoint analysis. It combines molecular geometry, orbitals, electron density, population analysis, electrostatic potential, reports, and a portable offline 3D workbench behind one typed calculation model.

Read the complete documentation

Installation

pip install openwfn

Quick Start

Run openWFN on a Gaussian formatted checkpoint file:

openwfn molecule.fchk summary
openwfn molecule.fchk geometry distance 1 2
openwfn molecule.fchk orbitals frontier
openwfn molecule.fchk population mulliken
openwfn molecule.fchk density integrate
openwfn molecule.fchk workbench molecule-workbench.html

If no subcommand is given:

• in a TTY terminal, openwfn launches interactive mode
• in non-interactive use, openwfn runs summary

Supported Input

openWFN accepts both Gaussian .fchk and .chk files.

• .fchk files are read directly
• Gaussian .chk files are proprietary binary files. openWFN does not decode them directly; it calls Gaussian's formchk utility when that executable is available in your PATH. Users without Gaussian should supply a formatted .fchk file.

You can also run checkpoint conversion explicitly:

openwfn molecule.chk formchk
openwfn molecule.chk formchk molecule.fchk

Analysis commands

• summary — molecular system summary
• info — formatted checkpoint metadata
• geometry distance|angle|dihedral — typed geometry analysis
• bonds — detected covalent bond network
• graph — fragment and connectivity graph
• orbitals frontier — HOMO, LUMO, and energy gap
• population mulliken|lowdin — atomic populations and charges
• density integrate|cube — numerical density integration and cube export
• esp point — nuclear, atomic-charge, or grid-based potential at a point
• report build — reproducible HTML or Markdown research report
• workbench — self-contained offline analysis and visualization workspace
• xyz output.xyz — export Cartesian coordinates
• view — export a standalone local HTML molecule viewer
• formchk [output.fchk] — convert a Gaussian checkpoint into a formatted checkpoint

Viewer

view exports a fully local standalone HTML viewer powered by bundled 3Dmol.js.

By default it:

• writes a shareable .html file in the current working directory
• keeps the viewer self-contained in a single file
• does not open the browser unless you request it

The exported viewer supports:

• atom labels
• local 3D rendering styles
• built-in downloads for XYZ, PDB, SDF, PNG, JPEG, and SVG

Examples:

openwfn molecule.fchk view
openwfn molecule.fchk view --open
openwfn molecule.fchk view --save viewer.html

Example Sessions

openwfn examples/water/water.fchk summary
openwfn examples/water/water.fchk dist 2 1
openwfn examples/water/water.fchk angle 2 1 3
openwfn examples/methane/methane.fchk graph
openwfn examples/water/water.fchk view --save water_viewer.html
openwfn examples/water/water.fchk

Capability status

openWFN labels scientific capabilities explicitly:

• Stable: parsing, geometry, topology, frontier orbitals, population analysis, nuclear/atomic-charge ESP, reports, exports, and the Python API.
• Validated: total-density grid integration and cube export for the active provenance-backed validation set.
• Experimental: electronic and total ESP obtained from numerical density grids.
• Unsupported: analyses whose required records or scientific validation are absent.

See the validation matrix and documented limitations before using results in research.

License

MIT License. See LICENSE.