[gmx-users] microcanonical

Mark Abraham Mark.Abraham at anu.edu.au
Sun May 21 03:10:57 CEST 2006


karamyog singh wrote:
> I guess since after the first run, the forces between atoms is not 
> zero(only negligible), when i do the 2nd run, the atoms start moving 
> under the action of these forces and since there is no temperature 
> scaling or pressure scaling, we can or might see an increase in KE as in 
> my case. So an increase might be correct.

If you are doing constant energy, if the PE is not changing (much) then 
neither should the KE. If KE is increasing *over* time, while PE is 
staying the same then you can't be doing NVE. The most likely suspect 
here is the use of cutoffs, like I have been saying all along. The use 
of (electrostatic) cutoffs is well known to cause heating in NVE 
simulations.

Mark




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