[gmx-users] density off

[David van der Spoel]

On 2011-04-20 20.10, Juliette N. wrote:
> Hi David,
>
> I used to apply NPT to fix the density, how can I get the denisty using NVT?
>
You turn off P coupling and fix the right density by scaling using editconf.

> On 20 April 2011 13:46, David van der Spoel <spoel at xray.bmc.uu.se
> <mailto:spoel at xray.bmc.uu.se>> wrote:
>
>     On 2011-04-20 19.40, Juliette N. wrote:
>
>         Hello,
>
>         I am trying to obtain the density for my system that is exactly
>         identical to experimental value but whatever pressure I apply
>         density is
>         still off by 3%.
>         Is this issue common?
>         --
>         Thanks,
>         Jennifer N.
>
>     Yes, force fields are not perfect.
>     How about running NVT at the experimental density and measuring the
>     pressure?
>
>     --
>     David van der Spoel, Ph.D., Professor of Biology
>     Dept. of Cell & Molec. Biol., Uppsala University.
>     Box 596, 75124 Uppsala, Sweden. Phone:  +46184714205.
>     spoel at xray.bmc.uu.se <mailto:spoel at xray.bmc.uu.se>
>     http://folding.bmc.uu.se
>     --
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>
>
> --
> Thanks,
> Jennifer N.
>


-- 
David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
spoel at xray.bmc.uu.se    http://folding.bmc.uu.se