Date: Wed, 24 Jul 2002 12:58:25 -0700
From: "David A. Case"
Subject: Re: am1-bcc charges, antechamber

On Wed, Jul 24, 2002, Sophia Kondratova wrote:

> I am trying to calculate am1-bcc charges. I have installed mopac7 and it seems
> to be working properly. Using gaussian98 am1 output, when I try to run the
> following command
> antechamber -i input -fi gout -o output -fo ac -c bcc, the following error
> comes up:
>
> Running: /usr/local/amber7/exe/mopac.sh ANTECHAMBER_MUL.MOP
> ANTECHAMBER_MUL.OUT
> Unable to find mopac charges in ANTECHAMBER_MUL.OUT

First, antechamber doesn't know how to find AM1 charges in Gaussian outputs;
furthermore, as far as I can tell, Gaussian only computes Mulliken charges
(not the Coulson charges that are required). So (unless there is some way
to get Gaussian to do what is needed) Gaussian output will not be of much
help to you, and there is no "fix" to antechamber that would help.

[Aside to the list: does anyone know a way to get Gaussian to give Coulson
charges for AM1 calculations? If so, this could be a useful alternative
for some (many) people to using mopac.]

You need to check if your /usr/local/amber7/exe/mopac.sh file needs to
be edited: see the comments in that file. It needs to run the mopac7 you
installed, and to handle the file names in a certain way. You should have
a file called ANTECHAMBER_MUL.OUT that is the mopac output; antechamber
then parses this file to get the charges. It looks like your mopac.sh
script has somehow not created this file. To be of more help, I'd need
more information.

[But yet another aside: I have never been able to find a version of mopac7
that works for me, e.g. just compiling under g77 and giving correct results.
I've solicted suggestions from the CCL list, but none of the suggested
responses would work (again, for me). Certain compilers or "magic options"
generally seem to be required, and I've had reports that the Merz group at
Penn State has figured this out. Comments from mopac-gurus would be
appreciated; see the comments on p.8 of the users' manual for a pointer to
a version of mopac5 that I have used.]

>
> I tried to calculate just the mulliken charges by:
> antechamber -i input -fi gout -o output -fo ac -c mul. The ac file was
> created, but it had no charges in it.

Sorry, I've never tried this option.

..good luck...dac