Subject: Gaussian03: BOMD

From: "Nicolas Ferre'" <ferre=at=unisi.it>
Date: Fri, 29 Aug 2003 11:08:27 +0200

Hi,

I'd like to know a little bit more about running Born-Oppenheimer MD in
g03. First, is it possible to carry on MDs without informations about
the Hessian ? Unfortunately, the GradientOnly keyword does not seem to
work, but I found the corresponding IOp: 1/71=-1. Anyway, even if I
include this IOp, the job starts with the calculation of an analytical
Hessian. By the way, is it possible to switch to a numerical one ?
At first sight, it seems that a first job devoted to the calculation of
the numerical Hessian must be done, then that this Hessian should be
read at the beginning of the MD using IOp(1/10=5). Is it the only way ?
Last question: is it possible to freeze the position of some atoms ?
Alternatively, is it possible to add some point charges ?
That's all for now. Thanks for any light.

Nicolas

-- 
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Nicolas FERRE' (PhD)
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Dipartimento di Chimica
Universita` di Siena             mailto:ferre=at=unisi.it
via Aldo Moro
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