Subject: Re: CCL:Can dynamics pressure of the MD simulation compared with surface tension?

From: Rick Venable <[email-masked]>
Date: Thu, 16 May 2002 12:12:52 -0400

On Thu, 16 May 2002, [gb2312] yong pei wrote:
>     I want to know the relation between the dynamics
> pressure and the surface tension of liquid . 

It can be evaluated for systems with either planar interfaces or for a
droplet; there's a brief description for droplets in the "Computer
Simulation of Liquids" book by Allen & Tildesley (pp. 289-291).

You can find info on the CHARMM implementation and application to planar
interfaces (water/octane, bilayers) in the following refs:

   ZHANG YH, FELLER SE, BROOKS BR, et al.
    COMPUTER-SIMULATION OF LIQUID/LIQUID INTERFACES .1. THEORY AND
APPLICATION TO  OCTANE/WATER
    J CHEM PHYS 103 (23): 10252-10266 DEC 15 1995 

   FELLER SE, ZHANG YH, PASTOR RW
    COMPUTER-SIMULATION OF LIQUID/LIQUID INTERFACES .2. SURFACE-TENSION
AREA DEPENDENCE OF A BILAYER AND MONOLAYER
    J CHEM PHYS 103 (23): 10267-10276 DEC 15 1995 

   FELLER SE, ZHANG YH, PASTOR RW, et al.
    CONSTANT-PRESSURE MOLECULAR-DYNAMICS SIMULATION - THE LANGEVIN
PISTON METHOD
    J CHEM PHYS 103 (11): 4613-4621 SEP 15 1995 

An oriented ensemble (planar interfaces in XY plane) termed NPAT can be
used to evaluate the surface tension directly from the diagonal of the
pressure tensor as

	gamma = ( Pzz - (Pxx+Pyy)/2 )/2

for a system constructed with 2 planar interfaces.

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Rick Venable           29/500
FDA/CBER/OVRR Biophysics Lab
1401 Rockville Pike    HFM-419
Rockville, MD  20852-1448  U.S.A.
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