---
name: "obthermo"
section: "1"
platform: "linux"
package: "openbabel"
version: "3.2.1-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/obthermo"
---

# obthermo(1)

extract the thermochemistry for a molecule

## NAME

**obthermo** – extract the thermochemistry for a molecule

## SYNOPSIS

**obthermo** \[*OPTIONS*\] *filename*

## DESCRIPTION

The **obthermo** tool can be used to extract the thermochemistry, e.g. enthalpy and Gibbs energy of formation, and the standard entropy from e.g. a Gaussian calculation.

## OPTIONS

- **--symm** *N*

  override symmetry number used in input file

- **--nrot** *N*

  number of rotatable bonds for conformational entropy

- **--dbdt** *x*

  temperature derivative of second virial coefficient for cp calculation

- **--kj**

  output kJ/mol related units (default kcal/mol)

## SEE ALSO

[obabel(1)](/obabel/1.md).

The web pages for Open Babel can be found at: \<**https://openbabel.org/**\>

## AUTHORS

Open Babel is developed by a cast of many, including current maintainers Geoff Hutchison, Chris Morley, Michael Banck, and innumerable others who have contributed fixes and additions. For more contributors to Open Babel, see \<**https://openbabel.org/docs/Introduction/thanks.html**\>

## COPYRIGHT

Copyright (C) 1998-2001 by OpenEye Scientific Software, Inc.\
 Some portions Copyright (C) 2001-2008 by Geoffrey R. Hutchison and other contributors.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.