[gmx-users] surface tension calculation in g_energy

[Bo Zhou]

Hi all,

   I use the option "#Surf*SurfTens" in g_engery to calculate the surface
tension, but I find that I really do not know how it works after I get some
inconsistent results compared with the calculation using the formula "gamma
= 0.5*(Pzz - (Pxx+Pyy)/2) * Lz" ( there are two surfaces here and the
surfaces in normal to the Z-axis).

 

Energy                      Average       RMSD     Fluct.      Drift
Tot-Drift

----------------------------------------------------------------------------
---

#Surf*SurfTen                1136.5    2557.05       2557 0.00852598
51.1559

 

<======  ###############  ==>

        <====  A V E R A G E S  ====>

        <==  ###############  ======>

   Pressure (bar)

   -1.93061e+02   -6.88599e-01   -1.66823e-02

   -6.84564e-01   -1.93953e+02   -2.93803e-02

7.79006e-03   -6.97915e-03   -9.87987e+01

 

The "#Surf*SurfTens" gives a value 568.25 bar*nm, and "gamma = 0.5*(Pzz -
(Pxx+Pyy)/2) * Lz" gives a value 473.54 bar*nm. Please give me some
suggestions about the inconsistency. Thanks in advance.

 

 

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