AMBER Archive (2003)

Subject: RE: about the dielectric

From: Yong Duan (yduan_at_udel.edu)
Date: Wed May 28 2003 - 04:24:58 CDT

Dear Ye Mei,

AMBER force field (94 and later) has been based on Cornell et al charge
set which was developed using HF/6-31G* which, in turn, exaggerates
electrostatic potential somewhat. This is similar to solvent
polarization effect., although solvent polarization is more local.
Therefore, the charge set behaves likes a condensed-phase charges. In
other words, the condensed phase is its "native" phase.

If your intention is to simulate the behavior of the molecule in
gas-phase, you probably should use a dielectric constant between 2.0 to
4.0.
In condensed phase, epsilon should be set to 1.0.

Yong Duan, Ph.D
Department of Chemistry and Biochemistry
University of Delaware
Newark, DE 19716

-----Original Message-----
From: Ye Mei [mailto:ymei_at_itcc.nju.edu.cn]
Sent: Wednesday, May 28, 2003 3:42 AM
To: amber mailing list
Subject: about the dielectric

Hello,

        I have a question about the dielectric in Amber force field.
What are the right values of the epsilon for the energy calculation in
gas phase and in the aqueous solution?
    Thank you in advance.
　　　　　　
                                 
Best regards!
Ye Mei
ymei_at_itcc.nju.edu.cn
2003-05-28