Dear GMX users, I am working on a protein which I want to simulate in a lipid bilayer environment (POPC) and want to use OPLS force field for the same. I wanted to modify the parameter files of lipids taken from peter teilman site. Taking cue from chris neale (may 2006 gmx mailing list) I changed the c6 and c12 to sigma epsilon using formula Sigma = (c12/c6)^1/6 and epsilon = c6/(4*sigma^6) i tried it for the [pairtypes] in lipid.itp file, but the calculations I made using excel gave me the following:
[ pairtypes ] ; i j funct sigma epsilon LO LO 1 1.10E-01 2.96E-01 LO LOM 1 1.10E-01 2.96E-0 and so on i.e. the values of sigma and epsilon are interchanged, as opposed to the values listed by chris neale in archive mail (listed below) [ pairtypes ] ; i j funct sigma epsilon LO LO 1 2.96E-01 1.10E-01 LO LOM 1 2.96E-01 1.10E-01 LO opls_116 1 3.06E-01 9.47E-02 LO LNL 1 3.10E-01 9.88E-02 LO LC 1 3.33E-01 7.76E-02 etc... I am doing something wrong or I can just interchange the values and use them accordingly. Thanking you Parul Tewatia -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists