Re: Pressure -ve

From: Sterling Paramore (paramore_at_hec.utah.edu)
Date: Wed Mar 08 2006 - 12:10:51 CST

The negative pressure just means that the box is bigger than it "wants"
to be. If you were to run NPT dynamics at P=0, the box would shrink
somewhat, but since you're doing NVE, the box dimensions cannot change.

-Sterling

Jérôme Hénin wrote:

>Tamal,
>
>This may indicate an improper equilibration. How long was the equilibration
>step, what kind of barostat/thermostat parameters did you use, and how did
>the periodic box dimensions (cf. .xst file) behave during that stage?
>
>Also, the question I should have asked first: what kind of system are you
>simulating?
>
>Jerome
>
>Le Mercredi 8 Mars 2006 15:49, Tamal Banerjee a écrit :
>
>
>>I am doing MD simulation in NVE ensemble.But having a negative GPRESSURE
>>and PRESSURE.What does that indictate.Prior to that i have done the
>>minimization,heating and equilibriation steps.
>>
>>Kindly look at the
>>
>>ETITLE: TS BOND ANGLE DIHED
>>IMPRP ELECT VDW BOUNDARY MISC
>> KINETIC TOTAL TEMP TOTAL2
>>TOTAL3 TEMPAVG PRESSURE GPRESSURE VOLUME
>> PRESSAVG GPRESSAVG
>>
>>WRITING COORDINATES TO DCD FILE AT STEP 832000
>>TIMING: 833000 CPU: 114358, 0.197719/step Wall: 114358, 0.197718/step,
>>9.17192 hours remaining, 0 kB of memory in use.
>>ENERGY: 833000 2901.9982 83540.1370 589.4835
>>1.4493 -11176.6125 -4284.2485 0.0000 0.0000
>> 5125.9289 76698.1358 509.6789 76712.3288
>>76713.0510 504.0505 -1093.4390 -1097.6505
>>129880.6603 -984.1841 -984.1256
>>
>>
>>Kindly advise
>>
>>Tamal
>>
>>
>
>
>

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