This task is devoted to introduce GROMACS notation for force fields. We build the model of hydrazine molecule, introducing lone electron pair as an artificial atom. We set molecular conformations with pairs or by defining dihedral potential. Varying dihedral potentials or pairs we obtain different equilibrium conformations of hydrazine.

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ERG group members work with different types of molecules and consequently added new atomtypes into classical OPLS-AA distributed with GROMACS. Now the ERG patch of OPLS-AA force field is published at bitbucket as a repository.

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OPLS-AA topology generation is a very complex task because of huge amount of the atomtypes described this force field. The OPLS-AA force filed contains more than 800 atom types that is nevertheless not sufficient for describing all the diversity of chemical structures. Thus, as parameters for new chemical fragments appears in literature the atomtype database […]

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(ATTENTION! MATERIAL UPDATED!) For lipid bilayer modelling the whole toolchain was built: from creating membranes to MD trajectory analysis. We use OPLS-AA forcefield with Berger potentials for alcane dihedrals integrated. Addings to OPLS-AA Forcefield. We use OPLS-AA with some includings; «includings» are overlays on the standart GROMACS forcefield files. Patch for GROMACS OPLS-AA forcefield  is […]

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To build topology for the new molecule partial charges for atoms should be determined. Working in OPLS force field big amount of atom types with predefined partial charges allows you to chose atom type for almost every atom of your «new» compound. But In rest force fields you have no choice except use quantum chemistry […]

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