[gmx-users] Changing Dielectric constant

[Erik Lindahl]

There is actually an option in the mdp file to change the dielectric 
constant directly, it's called epsilon_r. However, as other people have 
warned this only scales down the interactions by changing the vacuum 
dielectric constant. Even when you use the default epsilon_r=1, a water 
model like SPC provides a macroscopic dielectric constant around 60, 
and TIP5P reaches 80. All recent force fields are parameterized for 
epsilon_r=1.

Cheers,

Erik

On Mar 5, 2004, at 2:09 PM, Marc Baaden wrote:

>
> Hi,
>
> you can modify the dielectric constant by using a user tabulated
> interaction function, mdrun option -table. Check the manual and
> the mailing list archives for more details.
>
> Marc
>
>>>> Gaurav Porwal said:
>>> Dear Gromacs users,
>>>
>>> How can I change the dielectric constant of the medium in which I'm
>>> carrying out the simulations. I can't see any option about this in 
>>> the mdp
>>> file.
>>>
>>> Thanks in advance.
>>>
>>> Regards,
>>> Gaurav
> -- 
>  Dr. Marc Baaden  - Institut de Biologie Physico-Chimique, Paris
>  mailto:baaden at smplinux.de      -      http://www.marc-baaden.de
>  FAX: +49 697912 39550  -  Tel: +33 15841 5176 ou +33 609 843217
>
>
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