Re: Conversion from c6 and c12 = 0 to sigma epsilon

From: Brian Radak (bradak_at_anl.gov)
Date: Sat May 14 2016 - 15:39:48 CDT

For zeroed LJ interactions you can use epsilon = 0 and any Rmin/2 value
you choose. If you don't want to zero _all_ interactions with atoms of
that type, then you should add an NBFix.

On 05/14/2016 06:29 AM, Sourav Ray wrote:
> Greetings
>
> For two particles without LJ interaction, the c6 and c12 values (in
> GROMACS topology file) are set to 0. If I would like to incorporate
> the same to a CHARMM parameter file, I need to convert them to
> sigma-epsilon form.
>
> Since the usual conversion formula will result in 'divide by 0' error.
> I presume we can set epsilon = 0 and sigma to some arbitrarily high
> value well beyond the LJ cut off (or any random value because epsilon
> is zero), any suggestions?
>
> Thanks and regards
> Sourav

-- 
Brian Radak
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory
9700 South Cass Avenue, Bldg. 240
Argonne, IL 60439-4854
(630) 252-8643
brian.radak_at_anl.gov

This archive was generated by hypermail 2.1.6 : Sun Dec 31 2017 - 23:20:25 CST