Hi Justin, Thanks for your reply but am getting error suggesting a intermolecular chemical bond is not allowed:
Program: gmx grompp, version 2016.4 Source file: src/gromacs/gmxpreprocess/convparm.cpp (line 649) Fatal error: The intermolecular_interaction can not contain chemically bonding interactions [ molecules ] ; name number molA 1 molB 1 W 2420 [intermolecular_interactions] [ bonds ] 1 158 1 0.4 2000 This is coarse-grained model and as a simple test I used global atom numbers between two water single particles (intermolecular) but I get the same error. regards, Dave On Mon, Oct 28, 2019 at 5:58 AM Justin Lemkul <jalem...@vt.edu> wrote: > > > On 10/27/19 9:24 PM, Dave M wrote: > > Hi All, > > > > I am trying to define a bond between two molecules. Their parameters are > > defined in separate itp files: molA.itp and molB.itp. I know I can > > combine both the itp files but I am just wondering if I can define extra > > bonds/angles joining two molecules in a separate itp file taking care of > > atom numbers. To test it I defined an extra bond joining two atoms > (elastic > > bond) from two molecules in a separate bond.itp file but it does not look > > like molecules come close at all. > > Not sure this is a correct way. And, also is there a way I can print the > > bond parameters from tpr file to confirm whether all the bonds and angles > > are read from itp files. > > > > My top file looks like this > > > > #include "mol1.itp" > > > > #include "mol2.itp" > > > > #include "bond.itp" > > > > > > [ system ] > > > > test > > > > > > [ molecules ] > > > > ; name number > > > > molA 1 > > > > molB 1 > > You don't even need a separate .itp file. After you define [molecules], > you can add an [intermolecular_interactions] directive like so: > > [intermolecular_interactions] > [bonds] > atom_i atom_j b0 kb > > Note that atom_i and atom_j, unlike individual [moleculetype] > definitions, refer to the global atom numbers in the coordinate file. > > -Justin > > -- > ================================================== > > Justin A. Lemkul, Ph.D. > Assistant Professor > Office: 301 Fralin Hall > Lab: 303 Engel Hall > > Virginia Tech Department of Biochemistry > 340 West Campus Dr. > Blacksburg, VA 24061 > > jalem...@vt.edu | (540) 231-3129 > http://www.thelemkullab.com > > ================================================== > > -- > 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. > -- 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.