AMBER Archive (2003)

Subject: RE: charge determination for polariable ff02 force fields

From: Xiang, Tian-Xiang (txian2_at_email.uky.edu)
Date: Sun Feb 16 2003 - 12:19:39 CST

A newer paper by Cieplak et al. (J. Compt. Chem. 22, 1048 (2001))
proposed a new method to determine charge sets. That is the method I
have a hard time to follow. Specifically, How to determine ESP due to
induced dipoles, or ESP(ind), and ESP(QM)-ESP(ind)?

Thanks
  

Tian-xiang
 
-----Original Message-----
From: Lepsa [mailto:lepsik_at_marilyn.uochb.cas.cz]
Sent: Saturday, February 15, 2003 10:48 AM
To: Xiang, Tian-Xiang
Subject: Re: charge determination for polariable ff02 force fields

Dear Tian-xiang,
I'm not an expert on polarizable FF but this is how I understand it. You
optimize your molecule
at HF/6-31G*, then compute ESP by B3LYP/cc-pVTZ. Then you fit the
charges
by RESP.
With these charges you enter the simulation and the iterative procedure
to
obtain the polarization
energy contribution is done by e.g.SANDER. For details, see Wang JM,
Cieplak
P, Kollman PA
How well does a restrained electrostatic potential (RESP) model perform
in
calculating conformational energies of organic and biological
molecules?J
COMPUT CHEM 21: (12) 1049-1074 SEP 2000

Hope this helps.

Beste regards,

  Martin
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Martin Lepsik, PhD student            Phone:  +420/2/20183-540, Fax:
+420/2/20183-292
Dept. of Theor Chem & Center for Complex molecular Systems and
Biomolecules
Institute of Organic Chemistry and Biochemistry (IOCB)
Flemingovo nam 2,
Czech Academy of Sciences,
166 10, Prague 6,
Czech Rep.
URL: www.uochb.cas.cz/~teochem