On 6/29/19 12:39 PM, Peter Stern wrote:
No, of course not. United atom potentials are optimized taking into account that the hydrogens are not included. Think about it. If you use the United atom dihedral potential in an all-atom force field you will also be adding to that all the dihedral potentials which include the hydrogen atoms. Clearly this is not going to be the same for a particular C-C bond. And in general, you cannot transfer parameters from one force field to another. I think that has been emphasized repeatedly in this forum.
100% agree with everything Peter has said above and I will add this (I have said it before but will say it again): dihedrals do not correspond to any real physical force. They are mathematical Band-Aids that account for inaccuracies in our treatment of nonbonded terms in 1-4 interactions. Some force fields apply scaling factors to these interactions, others do not. In any case, a dihedral term is absolutely connected to a force field parameter set (like other force field terms, but perhaps even more obviously so) because it is inextricably linked to the (1) atomic charges, (2) LJ terms, and (3) 1-4 scaling factor, if applicable.
-Justin -- ================================================== Justin A. Lemkul, Ph.D. Assistant Professor Office: 301 Fralin Hall Lab: 303 Engel Hall Virginia Tech Department of Biochemistry 340 West Campus Dr. Blacksburg, VA 24061 jalem...@vt.edu | (540) 231-3129 http://www.thelemkullab.com ================================================== -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
