Re: Hi: some doubt about nvt and npt equilibration

From: johan strumpfer (johanstr_at_ks.uiuc.edu)
Date: Sun Jul 03 2011 - 20:53:47 CDT

NVT = constant volume, constant temperature and constant particle number.
NPT = constant pressure, constant temperature and constant particle number.

i.e., if you turn off the pressure control, you don't have constant
pressure anymore, thus NVT.

------------------------------------------------------------------------------------------------------
Johan Strumpfer:         johanstr_at_ks.uiuc.edu        www.ks.uiuc.edu/~johanstr
Theoretical and Computational Biophysics Group
3115 Beckman Institute
University of Illinois at Urbana-Champaign
405 N. Mathews
Urbana, IL 61801, USA
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On Sun, Jul 3, 2011 at 8:36 PM, bharat gupta <bharat.85.monu_at_gmail.com> wrote:
> Hi,
> I want to know that the following parameters are for npt or nvt
> equilibration :-
>
> dielectric    1.0
> coordinates    ../common/complex_ionized.pdb
> outputEnergies 1000
> binaryoutput no
> DCDFreq    1000
> restartFreq 1000
> binCoordinates ./complex_min.restart.coor
> binaryrestart   yes
> structure       ../common/complex_ionized.psf
> paraTypeCharmm on
> parameters   ../common/par_all27_prot_na.prm
> exclude        scaled1-4
> 1-4scaling    1.0
> switching    on
> switchdist    8.0
> cutoff        12.0
> pairlistdist 13.5
> margin        2.0
> stepspercycle 20
> extendedSystem     ./complex_min.xsc
> outputname         equilibrated
> # Periodic Boundary Conditions
> #cellBasisVector1    62.6    0.0   0.0
> #cellBasisVector2     0.0   52.0   0.0
> #cellBasisVector3     0.0    0.0   46.6
> #cellOrigin          8.35   69.64  -10.16
>
>
> berendsenPressure                  on
> berendsenPressureTarget            1.01325   # atmospheric pressure
> berendsenPressureCompressibility   4.57e-5   # liquid water
> berendsenPressureRelaxationTime    100.0
> berendsenPressureFreq              10
> temperature          0.5      # starting at 0.5 K
> reassignFreq         100
> reassignIncr         0.5
> reassignHold         300      # target T: 300 K
> numsteps   100000
>
>
> If its for npt, what changes are needed to make it for nvt or vice versa??
>
>
> --
> Bharat
> Ph.D. Candidate
>
>

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