[AMBER] charge fitting procedure in amber

From: conor parks <coparks2012.gmail.com>
Date: Mon, 14 Dec 2015 16:27:21 -0500

Hello everyone,

I was wondering if someone could help me understand which charge fitting
procedure is appropriate for my case. I am trying to find the GAFF force
field parameters for methanol using tutorials (
http://ambermd.org/tutorials/basic/tutorial4b/). I am planning to perform a
glycine methanol water crystal growth simulation. I am not sure if it is ok
for me to use the BCC charge fitting scheme vs. RESP. The majority of the
tutorials I have found online use the BCC fitting procedure, and the manual
states the following, making me think the BCC and RESP methods should yield
equivalent physics:

The charge methods used in GAFF can be HF/6-31G* RESP or AM1-BCC.[285, 286]
All of the force field parametrization were carried out with HF/6-31G* RESP
charges. However, in most cases, AM1-BCC, which was parametrized to
reproduce HF/6-31G* RESP charges, is recommended in large-scale
calculations because of its efficiency.

Could someone help guide me into determining whether this is something I
need to worry about? I have been trying to generate the charges using RESP,
but have been having issues generating the gaussian input file.

Conor Parks
B.S.E in Chemical Engineering, University of Michigan, 2012
PhD candidate in Chemical Engineering, Purdue University
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Received on Mon Dec 14 2015 - 13:30:06 PST
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