All these parameters are for Mg2+, forgot to mention.
On Fri, May 31, 2013 at 10:48 PM, tarak karmakar <[email protected]>wrote: > Dear All, > > I have a little confusion with the non-bonding parameters conversion from > OPLS-AA to CHARMM in gromacs. > If I see the ffnonbonded.itp in both the cases I get the following numbers > > OPLS-GROMACS > > Sigma = 0.1644471 nm > Epsilon = (0.875044*4.184) = 3.66118 kJ/mol > > > ................................................................................................................................................................. > CHARMM-GROMACS > > Sigma = 0.21114299 nm > Epsilon = 0.06276 kJ/mol > > Now, from the charmm27 parameters file I get > CHARMM27 > > Rmin/2 = 1.18500 Ang > Epsilon = -0.0150 kcal/mol > > Converting these charmm parameters to gromacs formate I have to do > following conversions > > Sigma = 2^(5/6) * (Rmin/2) = 2^(5/6) * 1.185 = 2.1114299 Ang = 0.2114299 nm > Epsilon = 0.0150 * 4.184 = 0.06276 kJ/mol > > .................................................................................................................................................................... > > So, CHARMM (par_water_ions.prm) to charmm(ffnonbonded.itp) is fine. But > the problem I'm facing to convert the OPLS(ffnonbonded.itp) to > CHARMM(ffnonbonded.itp). > > I apologize for making any confusion. > > > Thanks, > Tarak > -- gmx-users mailing list [email protected] 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 [email protected]. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
