[gmx-users] rc or rlist in minimum image convention?

[Juliette N.]

On 23 February 2012 20:07, Mark Abraham <Mark.Abraham at anu.edu.au> wrote:

>  On 24/02/2012 10:55 AM, Juliette N. wrote:
>
> Hi all,
>
> My average size is 2.9 nm obtained from NPT under large pressure and now I
> intend  to increase rc to 1.4 and rlist to 1.65 nm. I am just worried about
> violating minimum image convention.
>
>
> That probably violates the parametrization of your force field.
>
> Thanks Mark. You mean rc =1.4 for OPLS-AA is not appropriate? In the
original OPLSAA:   Optimized Intermolecular Potential Functions for Liquid
Hydrocarbons
I see rc of 15 A has been used for alkanes which requires rlist of around
15+2.5+17.5 A ! Please comment why I am violating parametrization? Thanks.

>
>
> 1- My question is which of rc or rlist is important for minimum image
> convention?
>
>
> The larger one. See manual 3.2.2.
>
>
>  If its rlist then I think I have to make a bigger system.
>
> 2- Will the simulation raise warning once half of the box size < rc or
> (rlist) ? I mean I want to make sure than over the course of simulation I
> am not breaching this rule.
>
>
> Under at least some circumstances such volume changes cause fatal errors.
> You can check for such after the fact with g_mindist -pi
>


Alright so I dont need to worry about it if simulation crashes under such
conditions..

>
> Mark
>
>
>
> Thanks for your guidance,
> J.
>
>
>
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