[gmx-users] pressure for ambient water

[Justin A. Lemkul]

Amit Choubey wrote:
> Hi Everyone,
> 
> I was doing MD with SPC waters and found something which i am not sure 
> how to explain.
> 
> I made a box of SPC water of dimension 4x4x4 nm^3 and filled with water 
> using grenbox .
> 
> I then did a nvt simulation at 300 K for 1 ns . I used berendsen 
> coupling and Reaction - Field for coulomb interaction. Cut off were all 
> set to 1 nm. Temperature did converge to 300 K. After this i turned of 
> nvt and did nve with RF-zero for another ns. Energy was well converged 
> during this (RMSD < 0.1 %). Temperature was also around 304 K (RMSD < 
> 1%). But the pressure was 1.1 Kilobar with a fluctuation of 20 % . I don 
> understand this, shouldnt this be around 1 bar ? Could some one suggest 
> whats on ?
> 

Since an NVE ensemble employs neither a thermostat nor a barostat, I don't know 
why you'd expect that.

-Justin

> Thank you,
> amit
> 

-- 
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Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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