[gmx-users] REMD run showing temperature range more than the equilibrated.

[Mark Abraham]

On Tue, Jun 4, 2013 at 12:51 PM, suhani nagpal <suhani.nagpal at gmail.com>wrote:

> Hi all !
>
> well, I'm working on REMD with 96 replicas, with temperature range 280K to
> 425.04K.
>
> The NVT equilibration works well and graphs plotted show almost the
> required temperature after equilibration.
>
> Then, after 3 ns of remd run , the edr -> xvg files show initial
> temperature atleast 40 -50 units up , and then gradually reduces to it's
> temperature.
>
> for example
> replica 0 has 280 temperature , for initial 40 ps, it shows temperature up
> till 335K an then, decline.
>

Sounds like you're re-generating velocities, or mismatching input files.


>
> and around 21st to 22nd replica, the exchange probability is varying a lot
> from 20% to 60%.
>
> so, my queries are
>
>  how to resolve this temperature issue and why is the exchange probability
> so abrupt at 21-22 replica ?
>

Can't say. Might even be real!

Mark