[gmx-users] lipid monolayer isotherm

[Hector Mtz-Seara]

Sorry after reading again and again there is one question I'm not sure 
about.

> <>
> g_energy output gives surface pressure, not surface tension.

I've been reading the gromac's manual an in 7th character , page 138 , 
first paragraph, it speaks about surface tension, not surface pressure. 
In the option list of g_energy also speaks about #Surf*SurfTen. Then why 
you say the output is the surface pressure?. If you are right then where 
is the value of the surface tension of the water to make this output in 
the gromacs program. By the way it then means that you can only 
calculate "surface pressure" for monolayers in pure water systems?. Can 
you explain me that a little more.

> <>to compute the <><>surface tension you have to use the standard 
> expression:
>
> gama = gama_0 - pi
>
> where:
>
> gama = surface tension
>
> gama_0 = pure water surface tension
>
> pi = surface pressure
>
> anyway, if you're getting surface pressures 3-fold larger than that
> of pure water, then your surface tension is negative, isn't it? if
> that happens to be the case, then your systems may be still away
> from mechanical equilibrium.
>
> maybe you could give some more details of your simulations: how did
> you assembled each monolayer? how long was each simulation run? if
> you plot surface area along the simulation time, is it stable?
>
> best regards,
>
> andre'
>
> /-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/
>
> Dr. Andre' Farias de Moura
>
> /-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/
>
> Laboratorio de Quimica Teorica
> Universidade Federal de Sao Carlos
> Sao Carlos - SP - Brasil
>
> /-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/
>
> Endereco Atual
>
> Grupo de Quimica Quantica
> Instituto de Quimica de Sao Carlos
> Universidade de Sao Paulo
> Sao Carlos - SP - Brasil
> Telefone: 55-16-3373-8055
>
> /-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/

<>
thank you in advance, Hector
<>--------------------------------------------------------------------------------------------
Hector Martinez-Seara Monne

 Universidad de Barcelona

Dept. Quimica Fisica<>hseara at netscape.net
--------------------------------------------------------------------------------------------

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20050118/40085fc6/attachment.html>