Hi, If you have time, I have a question about the OPLS parameters given in the files located in the "top" directory (for example, /usr/local/gromacs/share/gromacs/top/oplsaa.ff).
In the oplsaa.ff directory, there is a file atomtypes.atp. At the top of this file, it says: ; Types 1-134 are from the united-atom OPLS, which can be ; useful for solvents and/or CH2 optimizations (e.g. in lipids). ; Explicit all-atom parameters start with opls_135. Is it true that there _could_ be all-atom parameters in Types 1-134, the united-atom section? For example, I am trying to find parameters for carbon tetrachloride, CCl4. I have found these possibilities in atomtypes.atp: opls_122 12.01100 ; C CCl4 opls_123 35.45300 ; Cl CCl4 which, for example, have the following entries in ffnonbonded.itp: opls_122 CT 6 12.01100 0.248 A 3.80000e-01 2.09200e-01 opls_123 Cl 17 35.45300 -0.062 A 3.47000e-01 1.11295e+00 Clearly, these entries each correspond to individual atoms, even though opls_122 and opls_123 are in the "united-atom OPLS" section. I will be describing the remainder of my system using all-atom OPLS parameters (CCl4 is just the solvent; I will also have solute); is it likely reasonably safe to use the above parameters for C and Cl? In other words, I would be "mixing" parameters from the united-atom and all-atom sections, because I have been unable to find all-atom parameters for C and Cl in CCl4. Thank you! Andrew DeYoung Carnegie Mellon University -- 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