Shermo：A general code for calculating molecular thermodynamic properties
Latest version：2.0.2 (Release date: 2020-Jul-13)
Developer
Dr. Tian Lu (sobereva[at]sina.com. Beijing Kein Research Center for Natural Sciences, China)
Citation
If Shermo is utilized in your study, currently please cite it in your paper as follows:
Tian Lu, Qinxue Chen, Shermo: A general code for calculating molecular thermodynamic properties, ChemRxiv (2020) DOI: 10.26434/chemrxiv.12278801
PS: This preprint article has been submitted to an academic journal. After publishing, the preprint shown above will be updated to the journal version.
Download
Manual (with examples): Shermo_manual_2.0.2.pdf
Executable file: Shermo_2.0.2.zip (including executable files of Windows and Linux platforms)
The source code of Shermo (written in Fortran) can be freely obtained upon request.
Introduction
Shermo program is a free, general, easy-to-use and flexible code for calculating molecular thermochemistry data based on ideal gas assumption. Although most quantum chemistry programs have their own codes used to calculate thermochemistry data after performing frequency analysis, they are not as powerful and flexible as Shermo, and usually their outputs are inconvenient to read.
Features of Shermo
- Output file of frequency analysis task of various quantum chemistry programs can be used as input file, including Gaussian, ORCA, GAMESS-US and NWChem. Other programs can also utilize Shermo to compute thermochemistry data as long as they can generate the .shm file defined by Shermo.
- All common thermochemistry quantities can be calculated, including internal energy (U), enthalpy (H), entropy (S), constant volume heat capacity (CV), constant pressure heat capacity (CP) and partition function (q).
- Contributions of translation, rotation, vibration, electron to various thermochemistry properties are outputted in a very compact and clear format. Contribution of every vibrational mode can also be printed to understand their influences on the calculated properties.
- Temperature and pressure can be easily scanned.
- Conformation/configuration weights and weighted thermodynamic data can be obtained.
- The thermochemistry properties are calculated based on Rigid-rotor harmonic oscillator (RRHO) model. In order to better deal with low frequencies, two quasi-RRHO treatments are supported: Raising lower frequencies to a specific value, Grimme's entropy interpolation between harmonic and free-rotor approximations.
- Frequency scaling factors for ZPE, heating contribution to internal energy, entropy and heat capacity can be individually specified.
- Point group and rotational symmetry number can be automatically assigned.
- Shermo can not only run in interactive mode but also run in command-line mode, thus it can be easily incorporated into shell script for batch processing.
- Very easy to use. The program can be used without installation, and users do not need to prepare any running environment like Python
Update History
2020-Jul-12: Version 2.0.2. Fixed a bug: Rotation symmetry number cannot be identified for molecule of Td point group
2020-May-20: Version 2.0.1. Fixed the bug of loading frequency scale factor for heat capacity
2020-May-14: Updated version 2.0. Now electronic energy can be directly specified via the "E" parameter, and in the conformation weighted calculation, electronic energies can be directly specified in the list file.
2020-May-12: Initial release of version 2.0