Dear Justin, Thank you for your reply. When I choose l-J form potential for the non-bonded interactions between CH4 and CH4 using the parameters from another paper, I can get system pressure (25.5Mpa) in accord with experimental value at same conditions. However, when I used tabulated potentials to add the morse form potentials, I got the pressure 5Mpa. I am confusing whether the tabulated potential works with the morse form potential. Best, Zhengcai
> 在 2015年5月22日,01:54,Justin Lemkul <jalem...@vt.edu> 写道: > > > >> On 5/21/15 8:36 AM, zhangzhengc wrote: >> Dear all, I want to add the Morse potential for nonbonded interactions >> between CH4 and CH4. I used three table files each contain seven columns to >> add the H to H, H to C, and C to C Morse form interactions. I set >> Coulombtype=user, vdwtype=user , and Dispcorr = no, and add energrps and >> energrps_table in the mdp file. However, when I did NVT simulations, I didnot >> get accurate pressure for my pure methane system. Actually the pressure is 20 > > I don't know much about tabulated potentials, but a question to get the ball > rolling: > > How do you define "accurate" - from some previous run? Without tabulated > potentials? If the latter, it means your tables are wrong with respect to > whatever parameters gave the "right" behavior. > > -Justin > >> Mpa smaller. Could you tell what is wrong with my set or what I missed in >> adding tabulated potentials? I tested the using of tabulated potentials with >> LJ form potential, It works very well. Look forward to your reply, Sincerely >> yours Zhengcai, > > -- > ================================================== > > 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.