force constants for umbrella sampling

Ali RNAlo... at
Tue Apr 15 21:58:05 UTC 2008

I agree that NVE doesn't guarantee a well defined T for umbrella
sampling. I have been using NVE with velocity rescaling so I do know
the average T of my system is where I want it to be.

You will probably tell me that CSVR is probably the better way to go


On Apr 11, 3:21 pm, Teodoro Laino <teodor... at> wrote:
> Ali,
> On 11 Apr 2008, at 21:12, Ali wrote:
> > * I have been using NVE instead of NVT for the umbrella sampling.
> > Technically the equations for umbrella sampling work only with NVT or
> > NPT. Can this be a possible source of the problem?
> NVE?!?
> You may want an ensemble with a well defined T for umbrella sampling
> (you're
> computing free energies!).
> NVE does not guarantee that.
> > * Should the force constant of the biasing potential 'K' be similar to
> > the force constant of -kT log (P(r)) ? Or should it work even if the
> > force constants are very dissimilar?
> Please, have a look at the many papers/books on this topic.
> Teo

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