Hi Nikolay, Fixed charge. The polarizable ones have "pol" in their names. I should mention that Chimera 1.7 (development, daily build version) has been updated to use Ambertools 12, including newer force fields. The default force field in Chimera 1.7 is ff12SB. For all the gory details, one should consult the Amber documentation, but there is some information here: <http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/addcharge/addcharge...> ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Jul 5, 2012, at 11:33 AM, Nikolay Igorovich Rodionov wrote:
Hi all,
I just have a quick question. Is AMBER99SB a fixed charge or polarizable forcefield?
Thank you, Nikolay Rodionov