openWFN

██████╗ ██████╗ ███████╗███╗   ██╗██╗    ██╗███████╗███╗   ██╗
██╔══██╗██╔══██╗██╔════╝████╗  ██║██║    ██║██╔════╝████╗  ██║
██║  ██║██████╔╝█████╗  ██╔██╗ ██║██║ █╗ ██║█████╗  ██╔██╗ ██║
██║  ██║██╔═══╝ ██╔══╝  ██║╚██╗██║██║███╗██║██╔══╝  ██║╚██╗██║
██████╔╝██║     ███████╗██║ ╚████║╚███╔███╔╝██║     ██║ ╚████║
╚═════╝ ╚═╝     ╚══════╝╚═╝  ╚═══╝ ╚══╝╚══╝ ╚═╝     ╚═╝  ╚═══╝

openWFN is a command-line toolkit for molecular geometry, connectivity, and structure exploration from Gaussian checkpoint data. It is designed for fast terminal workflows around formatted checkpoint files, with a built-in local molecule viewer for lightweight inspection and sharing.

Installation

pip install openwfn

Quick Start

Run openWFN on a Gaussian formatted checkpoint file:

openwfn molecule.fchk summary
openwfn molecule.fchk dist 1 2
openwfn molecule.fchk graph
openwfn molecule.fchk xyz molecule.xyz
openwfn molecule.fchk view

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

Stable Commands

• summary — molecular system summary
• info — formatted checkpoint metadata
• dist i j — interatomic distance
• angle i j k — three-atom bond angle
• dihedral i j k l — four-atom dihedral
• bonds — detected covalent bond network
• graph — fragment and connectivity graph
• 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

Project Scope

The stable surface of openWFN is focused on:

• geometry analysis
• molecular connectivity and fragment inspection
• coordinate export
• local browser-based structure viewing

Experimental modules may exist in the codebase, but they are not presented as production-ready features.

License

MIT License. See LICENSE.