Dear Kamali,
> Thank you so much for your detailed reply. I have one follow-up question
> for you: Do you know if it is possible to use Antechamber to generate RESP
> charges using a level of theory other than HF/6-31G*?
I would answer try and see ;-) Antechamber (and R.E.D.) just take the
MEP computed by QM and perform charge fitting whatever is the QM
theory level...
You could also download R.E.D. III.x; modify the source code so that
the 'RESP-A1' charge model use the QM theory level of your choice...
regards Francois
PS If you need it we can modify the source of R.E.D. for you...
> On Thu, Jul 4, 2013 at 10:51 AM, FyD <fyd.q4md-forcefieldtools.org> wrote:
>
>> Dear Kamali,
>>
>> > I actually do have another question. I would like to generate charges
>> using
>> > a basis set besides HF/6-31G* and AM1-BCC, and I was wondering if (a) the
>> > RED Server has or will have such a potential, and (b) if you have any
>> > suggestions about generating charges with other, non-standard basis sets.
>>
>> The use of HF/6-31G* is related to implicit polarization requested in
>> the additive Amber force field model. See
>> http://ambermd.org/doc6/html/AMBER-sh-19.4.html#sh-19.4
>> Be aware of what you do when using MP2 or DFT methods. For instance
>> MP2/aug-cc-pTVZ is used in the non-additive/polarizable FF model.
>>
>> Concerning AM1-BCC, the later approach is supposed to be an
>> 'approximation/simplification' of the RESP approach. Considering that
>> HF/6-31G* cost nothing (from a cpu point of view) our days I do not
>> understand why one would need an 'approximation' of the RESP method...
>> and obviously approximation/simplification has nothing to do with
>> breaking chemical equivalencing (just my personal opinion)...
>>
>> R.E.D. Server charge models are described at:
>> http://q4md-forcefieldtools.org/REDS/popup/popkeyword.php
>> R.E.D. Server Development charge models are described at:
>> http://q4md-forcefieldtools.org/REDS-Development/popup/popkeyword.php
>>
>> regards, Francois
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Received on Sun Jul 07 2013 - 09:30:03 PDT
