[gmx-users] Anisotropic Pressure

[Berk Hess]

>From: Matteo Guglielmi <matteo.guglielmi at epfl.ch>
>Reply-To: Discussion list for GROMACS users <gmx-users at gromacs.org>
>To: GMX-LIST <gmx-users at gromacs.org>
>Subject: [gmx-users] Anisotropic Pressure
>Date: Fri, 15 Jun 2007 19:11:50 +0200
>
>Hello Folks,
>
>Is there any difference between these two anisotropic pressure setup?
>
>### 1st setup ###
>
>pcoupl                   = berendsen
>pcoupltype               = anisotropic
>tau_p                    = 5.0      5.0      5.0      0.0    0.0    0.0
>compressibility          = 4.53e-5  4.53e-5  4.53e-5  0.0    0.0    0.0
>ref_p                    = 1.025    1.025    1.025    0.0    0.0    0.0
>
>
>### 2nd setup ###
>
>pcoupl                   = berendsen
>pcoupltype               = anisotropic
>tau_p                    = 5.0      5.0      5.0      5.0    5.0    5.0
>compressibility          = 4.53e-5  4.53e-5  4.53e-5  0.0      0.0      0.0
>ref_p                    = 1.025    1.025    1.025    1.025  1.025  1.025
>

If the compressibility is zero, the corresponding unit-cell degree of 
freedom
will not change, so effectively there is no difference.

>
>Which one would you suggest for anisotropic coupling (solvated pore
>immersed into a membrane)

Neither, you should probably use surface-tension coupling.

Berk.

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