Forcefit：A code for deriving force constant of internal coordinates based on Hessian matrix
Forcefit has been fully replaced by the very powerful code Sobtop, please use Sobtop instead!
Latest version：0.9 (Release date: 2021-Jun-4)
Introduction of Forcefit
Forcefit a free Python code used to derive force constant of bond, angle, dihedral and improper dihedral using Seminario method based on Hessian matrix generated by frequency analysis task of Gaussian program. You need to optimize and perform frequency analysis for a molecule by Gaussian first, convert the resulting .chk file to .fch file via formchk, then edit a very simple input file of Forcefit, then you can immediately obtain force constant of the internal coordinate of your interest. Forcefit is particularly useful when you need to build your own force field of a rigid system.
Developer
Qinxue Chen and Tian Lu
Contact: sobereva[at]sina.com. Beijing Kein Research Center for Natural Sciences, China
If you encountered any difficulty in using Forcefit, or you found a bug, please feel free to contact us!
Download (Python code and manual)
Citation
If Forcefit is utilized in your work, please cite it in your paper as follows:
Qinxue Chen, Tian Lu, Forcefit code, http://www.keinsci.com/research/forcefit
Update History
2021-Jun-4: Version 0.9. First release