Dear gromacs users, I am trying to simulate liquid SO2 (Sulphur dioxide). So I tried to create an equilibrated structure of SO2 molecules using the gmx insert-molecules function. As I try to minimize the energy of the system, I always get this-
------------------------------------------------------------------------------------------------------------------------ Energy minimization has stopped, but the forces have not converged to the requested precision Fmax < 10 (which may not be possible for your system). It stopped because the algorithm tried to make a new step whose size was too small, or there was no change in the energy since last step. Either way, we regard the minimization as converged to within the available machine precision, given your starting configuration and EM parameters. ------------------------------------------------------------------------------------------------------------------------ I tried to analyze my .gro file that the gmx insert-molecules function is returning me and found that some of my SO2 have a bond in between them. Is this what causes the energy minimization to crash? Is there any way I can prepare an equilibrated system of liquid SO2 ? My SO2.itp file is like this (I made this an .itp because I wish to study this system along with some other molecules)- ------------------------------------------------------------------------------------------------------------------------ [ moleculetype ] ; Name nrexcl SO2 3 [ atoms ] ; nr type resnr residue atom cgnr charge mass typeB chargeB massB 1 opls_202 1 SR S 1 0.6512 32.07 ;qtot 0.6512 2 opls_326 1 SR O1 2 -0.3256 15.99940 ;qtot 0.3256 3 opls_326 1 SR O2 3 -0.3256 15.99940 ; qtot 0 ; opls_202 S 16 32.07 0.6512 A 3.61500e-01 1.2125232 ; opls_326 O 8 15.99940 -0.3256 A 3.00500e-01 0.47756176 [ bonds ] ; ai aj funct c0 c1 c2 c3 1 2 1 0.1434 635968.0 1 3 1 0.1434 635968.0 [ distance_restraints ] ; ai aj type index type' low up1 up2 fac 1 2 1 0 1 1.149 1.490 1.490 1.0 1 3 1 0 1 1.149 1.490 1.490 1.0 [ angles ] ; ai aj ak funct c0 c1 c2 c3 2 1 3 1 119.5 1359.8 ------------------------------------------------------------------------------------------------------------------------ I have also uploaded the .gro file that the gmx insert-molecules function is returning me after this text. SO2_box300.gro <https://docs.google.com/file/d/0B8p1k0KkNddyUEN3dzZRZE5keXM/edit?usp=drive_web> Thanks in advance. -- 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.