This information is in the Help page for this tool. You can click the Help button on the "Minimize Structure" dialog or see the copy on our website here: <https://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/minimize/minimize.html> Specifically, see the section "Force Field Parameters" and "nonstandard residues" <https://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/minimize/minimize.html#nonstandard> Short answer is that is uses GAFF (see details in link above) with the type of charges you chose in the dialog, from your image Gasteiger. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Jan 13, 2024, at 1:33 AM, Prabuddha Bhattacharya via Chimera-users <chimera-users@cgl.ucsf.edu> wrote:
Dear Sir
I would be grateful if you kindly let me know what force field is used by Chimera to optimize the geometry of a small organic molecule (not peptide) if I minimize the structure using the parameters as shared in the attached file.
Thank you
Kind regards
Prabuddha Bhattacharya