[ghemical-devel] 1,4-scaling in ghemical tripos-5.2 forcefield

[Tim Vandermeersch]

Sorry, attached wrong file...

On 3/13/07, Tim Vandermeersch <tim.vandermeersch at gmail.com> wrote:
> Hello,
>
> > and sorry for the late answer.
>
> No problem, I don't always answer that fast myself as you can see :)
>
> >I have not had time to look at the problem
> > yet, I only briefly looked at tripos-5.2 original paper. I tried to find
> > there what the 1,4 scaling factor should be, but I didn't find it so far.
> >
> > Do you know what the scaling factor should be in tripos-5.2?
>
> No, but it is not the value of the scaling factor that I need (In
> ghemical it's 0.5). Attached are three files:
>
> benzene.gpr: coordinate file for benzene in gpr format
>
> ghemical_benzene.log: output (individual interactions) for libghemical
>
> (this is done with a modified version of the libghemical SVN
> example2.cpp and some editing to mimic openbabel's output style. I
> could send you this patch if you would be interested
>
> openbabel_benzene.log: same for openbabel
>
> Comparing the log files:
> - for VDW interaction 1, 5 and 9:   0.5 * E_ghemical = E_openbabel
> - these interactions are the 1,4 interactions for the carbon atoms in the ring
> - openbabel scales them, libghemical does not.
>
> Is this a bug, or should these interactions not be scaled?
>
> Thanks in advance,
> Tim
>
>
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