Which dihedral parameters are needed in oplsaa_forcefield

Discussions about the force fields implemented in Hippo. For general force field discussions see Molecular Simulations -> Force fields.
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ldav
Posts: 8
Joined: Wed Jul 23, 2008 9:38 am

Which dihedral parameters are needed in oplsaa_forcefield

Post by ldav » Wed Aug 06, 2008 10:08 am

When performing some MC simulations, I added my own ligands. For one of them I had missing parameters (new atom types) and I had therefore to add them in the oplsaa_forcefield.dat file. When looking at the 'DIHEDRALTYPES:' section, it is written 'Type V1 V2 V3 V4', but in fact it seems that the parameters to add should be the 'V1/2 V2/2 V3/2' (from Maestro for instance) multiply by two.
Does Hippo needs the V1-V6 (truncated to 4) or the V1-V3 coefficients?

martin
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Posts: 38
Joined: Sun Jun 15, 2008 10:27 pm

Re: Which dihedral parameters are needed in oplsaa_forcefield

Post by martin » Thu Aug 07, 2008 2:37 pm

Hippo uses only V1, V2, V3 as in the 1996 OPLS-AA forcefield paper

You can convert parameters from gromacs to hippo units using the attached excel sheet.
Attachments
ConvertOPLS.xls
Convert gromacs to hippo units
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