Re: vdwGeometricSigma for OPLS in NAMD 2.6b1 Release

From: Joshua D. Moore (
Date: Sat Aug 13 2005 - 03:21:44 CDT

Ok, my knowledge of CHARMM is not very good.

The Epsilon,ij is already calculated with the geometric rule. Is this
correct? So there is no need to add an option for epsilon, correct?


Joshua Moore

On Wed, August 10, 2005 7:59 pm, Joshua D. Moore wrote:
> Hi,
> I wanted to thank everyone for adding OPLS support in the latest release
> of NAMD.
> However, only the geometric combining rule for sigma is added, right?
> OPLS-AA uses the geometric combining rule for both sigma and epsilon,
> which I have altered thanks to Ben Roberts in the LJTable.C file. Thanks
> again Ben! Is it possible to add an option (vdwGeometricEpsilon or
> similar) for the geometric combining rule for epsilon as well?
> Furthermore, some may wish to use the Lorentz-Berthelot mixing rules for
> interactions between unlike atoms in different molecules. These use the
> arithmetic mean for sigma and the geometric mean for epsilon. Would it be
> possible to add this? I have not investigated this much, especially with
> OPLS, but it is just a related thought.
> Thanks.
> Joshua Moore

This archive was generated by hypermail 2.1.6 : Wed Feb 29 2012 - 15:41:03 CST