AMBER Archive (2009)

Subject: Re: [AMBER] Some queries about pH simulation

From: Carlos Simmerling (
Date: Fri Oct 09 2009 - 13:59:17 CDT

Jason is correct, mod_phipsi.1 was replaced by the Roitberg/Simmerling
ff99SB parameters

>1. Page 172 of manual when I type the following command in tleap
> >loadAmberParams frcmod.mod_phipsi.1
> >it gives error message
> >Could not open file frcmod.mod_phipsi.1: not found
> *
> This is because the frcmod.mod_phipsi.1 no longer exists. To the best of
> my
> knowledge, this is due to the fact that these phi/psi torsion modifications
> are the basis of the SB modification of the ff99 force field. These
> parameters are now present in the leaprc.ff99SB file. Therefore, replace
> the commands "source leaprc.ff99" and "loadAmberParams frcmod.mod_phipsi.1"
> with the single command "source leaprc.ff99SB".
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