Pouya,

More generally, you should go decreasing the value of the integration
timestep until you find the largest value that gives you a constant total
energy. If 0.5 still gives you a rise in the total energy after a while,
decrease it further, and so on, until you get a constant total energy.

Marcos

On Mon, Nov 1, 2010 at 7:04 PM, Pouya Partovi <[email protected]>wrote:

> Thanks guys. Set it to 0.5 fs. Will post the results.
>
> Bests,
> Pouya
>
>
> ----- Original Message -----
> From: "Bartek Szyja" <[email protected]>
> To: [email protected]
> Sent: Monday, November 1, 2010 9:08:05 PM
> Subject: Re: [SIESTA-L] A (sort of general) MD question
>
> On Mon, 2010-11-01 at 18:35 +0100, Pouya Partovi wrote:
> > MD.LengthTimeStep is set to 1 fs.
>
> Try smaller value then. 0.5 fs should be better (depending on your
> system). And - of course - it will take twice as many steps to complete
> the run...
>
> Good luck,
> Bartek
>
>
>
> > ----- Original Message -----
> > From: "Bartek Szyja" <[email protected]>
> > To: [email protected]
> > Sent: Monday, November 1, 2010 7:19:19 PM
> > Subject: Re: [SIESTA-L] A (sort of general) MD question
> >
> > On Mon, 2010-11-01 at 15:26 +0100, Pouya Partovi wrote:
> > > Dear SIESTA users,
> > >
> > > I have a problem with a MD simulation I'm performing with SIESTA at 305
> > >  K. I have attached the T, KS_Energy, Tot_Energy and P versus steps
> > >  plots to this message. Although T, KS_Energy and P reach the
> > >  equilibrium quite soon, the total energy has a trend even on step
> > >  15,000.
> >
> > What timestep do you set in your calculations? 15 thousands of steps,
> > but how many picoseconds that is?
> >
> > Cheers,
> > Bartek
> >
>
>
>

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