On 9/9/15 7:29 AM, Maryam Kowsar wrote:
Hi dan I think that's not possible to change forcefield parameters and use the old defined forcefield like opls. When you change the parameters in .itp you should introduce your own forcefield. Try to have all the needed files of forcefield in a new folder and use that during making topology.
This is not true. Any force field can be modified or extended. A local copy of a modified force field is a safe recommendation, but in the case of simply adding new atom types, there's little harm that can be done.
-Justin
On Tuesday, September 8, 2015, Phwey Gil <ps...@case.edu> wrote:Hi, I am looking to specify my own parameters for LJ parameters. Using the OPLS forcefield, I only want to change the LJ parameters of some atoms. I have H2O, C8H16O2 (Octanoic acid) and C2H6O (Ethanol). I am using SPC/E for H2O, and OPLS for C8H16O2 and C2H6O. And I want to change the LJ parameters for the hydrogens in C8H16O2 only. I have tried specifying [ atomtypes ] in various places (In .top or .itp) using the following format: [ atomtypes ] H H 1.008 0.450 A 5.66387665E-4 2.80730518E-7 But I was not successful; I checked topol.tpr and the numbers are according to OPLS and not my specified values. Can someone give me advice on how to do this? I've checked the forums and I was not successful at finding the correct information. Best Regards, Dan -- Dan Gil Case Western Reserve University | Class of 2016 Researcher, Department of Chemical Engineering ps...@case.edu <javascript:;> -- 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 <javascript:;>.
-- ================================================== Justin A. Lemkul, Ph.D. Ruth L. Kirschstein NRSA Postdoctoral Fellow Department of Pharmaceutical Sciences School of Pharmacy Health Sciences Facility II, Room 629 University of Maryland, Baltimore 20 Penn St. Baltimore, MD 21201 jalem...@outerbanks.umaryland.edu | (410) 706-7441 http://mackerell.umaryland.edu/~jalemkul ================================================== -- 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.
