Sufian,
I have never run a liquid simulation using SIESTA. However, I have done
some
simulations of liquids using other codes.
(1) Is the number of H2O molecules, and the volume of your simulation cell,
consistent with the density of water?
This would give you the wrong pressure.
(2) Is your initial configuration of the H2O molecules "close" to the proper
liquid structure?
This would give you an unrealistically potential interaction, either
high or low, most likely high.
(3) Make sure that your initial configuration takes into consideration the
periodic boundary conditions.
As I said earlier, I have never used SIESTA for a liquid simulation.
However, the above 3 items are
definitely issues that I would consider if I were to use SIESTA in this
manner. I think all 3 could
cause the problem that you are reporting.
Best of luck,
Jason
On Sat, Dec 5, 2009 at 2:00 PM, <[email protected]> wrote:
> Dear Siesta Users
>
> I am trying to run a molecular dynamics simulation for a bunch of H2O
> molecules,i chose the Tini =800 K and Tfin= 300 K my run starts normally
> for the first one or two steps. but after that a huge fluctuations in
> temperature appear, it reached a couple of thousands of kelvins i,tried
> many options but i still has the same problem,
> can any body assist me in this problem?
> Thank you all,
>
> sufian
>
>
