Re: [AMBER] force field parameter and resp charge calculation

From: colvin <colvin4367.gmail.com>
Date: Wed, 30 Jun 2010 22:13:43 +0800

Dear francois,

thanks for the clarification! However, back to my question, why the
resp program in antechamber can't perform the fitting for my molecule?

Pls advice. Thanks.

On Wednesday, June 30, 2010, FyD <fyd.q4md-forcefieldtools.org> wrote:
> Colvin,
>
>> What i mean is that, i have done resp calculations on 24 conformations and
>> can i average the resp charges?
>>
>> As i read this from http://q4md-forcefieldtools.org/RED/FAQ-I.php
>
> These FAQ are old/outdated(2004!) (they should rewritten). Since that
> time R.E.D. has changed a lot, and we ALSO did learn a lot.
> You are right "charge averaging" is not correct in these FAQ-I:
> My mistake. Sorry for that... Thanks for pointing this out.
>
>> "Do you average RESP results on many orientations?"
>
> No, we do use charge fitting based on multiple-orientations and/or
> multiple-conformations and/or multiple molecules.
>
>>  "Yes, we do average RESP results on 'different' orientations: we called it
>> multi-orientation-RESP fit by analogy to the multi-conformational RESP fit,
>> see below"
>
> this is ambiguous you are right! multi-orientation-RESP fit is about
> "charge fitting" and not "charge averaging". There is not arithmetic
> mean in RESP charge fitting/derivation.
>
>> Or do i misunderstand your meaning?
>>
>> how many conformations should be use to be useful? is that depends on the
>> molecule itself?
>
> You can look at
> Cieplak et al Application of the multimolecule and multiconformational
> RESP methodology to biopolymers: Charge derivation for DNA, RNA, and
> proteins. J. Comput. Chem. 1995, 16, 1357-1377
>  & and also:
> http://www.rsc.org/Publishing/Journals/CP/article.asp?doi=c0cp00111b
>
> regards, Francois
>
>
>
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>

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Received on Wed Jun 30 2010 - 07:30:12 PDT
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