[gmx-users] vdw modifier and coulomb modifier

[Mark Abraham]

Hi,

On Fri, Oct 2, 2015 at 5:36 AM Parvez Mh <parvezmh89 at gmail.com> wrote:

> Dear all,
>
> What does vdw and coulomb modifier do in simulation?. Does these option
> affect simulation accuracy.


These are documented in the .mdp options parts of the manuals. They have
various effects on your model physics. You should choose them to match your
simulation needs, particularly with respect to the force field you are
intending to use.


> I did not find these term in literature or any
> book, why did gromacs introduce these option?
>

Several MD packages and/or force fields do various different things with
short-ranged non-bonded forces. Sometimes they call different things by the
same name (and vice-versa). Some of the things are still thought to be
sensible to do. :-) Some of the things are even documented. In general, you
should understand the equations they claim to implement, and do your own
numerical experiments! :-)

When there are multiple basic kinds of thing and several ways one might
vary some them, it is convenient to describe both the theme and variant,
rather than combine both into one name. Thus "modifiers."

Mark


> Thanks
> Masrul
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