[gmx-users] C6 and C12 in ffgmxnb.itp

[David van der Spoel]

On Wed, 2003-12-10 at 17:15, Albert Sun wrote:
> Dear Users,
> 
> I used parameters of C6 and C12 in ffgmxnb.itp to compute potential,
> the results are all  negative, this looks incorrect.
> 
> In ffgmxnb.itp file,  for example C-C nonbond,  C6= 0.0023402KJ/mol, 
> 
> C12 = 0.33740E-05 nm.
> 
you are mixing this stuff up with sigma and epsilon ntoation. see manual


> But in other literatures,  some researchers used C6 is about 0.
> 5KJ/mol and C12 is about 0.4nm, this will get positive potential.
> 
> Do you think the parameters in ffgmxnb.itp is correct?
> 
> Thanks for your advice.
> 
> Albert
> 
>  
> 
> 
> 
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-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assist. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://xray.bmc.uu.se/~spoel
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