[gmx-users] tau_p

[Mark Abraham]

> Dear all,
> I am running md simulations on a decapeptide, using pressure coupling
> [npt].
> My box is octahedral and box dimensions are set at peptide length plus
> twice
> the cut-off as recommended. I have set tau_p to be 1.0 ps. After 1 ns ,
> the
> average pressure had come down to 2.6 bar, though fluctuations were quite
> high. [Standard deviation 150.8 ] But after 6ns, the pressure has risen
> again to 4.6 bar. Can you please advise me on this?

What was your equilibration regime? Over what length of time are you
calculating these average pressures?

> Also, can you please
> tell me if there is any correlation between pressure average and tau_p
> values?

Yes, there will be for a properly set-up system.

Mark