Hi Andrey I have 16-H2O molecule in my unit cell, i am trying to cool the system down from 1000K to 300K to be more realistic. The problem still there, the temperature goes very high and won't stop at the target temperature, i tried to use annealing, Nose,... all those options give the same problem, i am wondering if there is any unseen option that can be used to fix this problem?
yours, sufain > Hi Sufian, > > How many molecules does your "bunch" contain? It's normal to have > temperature fluctuations of ~T/sqrt(N), where N is the number of > particles. Also I encountered non-physical temperature fluctuations > when initial temperature of run was not equal to final temperature. > Seems that Nose thermostat in Siesta is not capable to implement > temperature gradients. And the final remark - if you want to model > gas-liquid phase transition, Siesta might not be the right tool to do > it, since it needs a big supercell and large simulation time. > > Cheers, > Andrey. > >> 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 >> >
