From young@slater.cem.msu.edu  Thu Oct 21 07:07:37 1993
Date: Thu, 21 Oct 93 11:07:37 -0400
From: young@slater.cem.msu.edu (Dave Young)
Message-Id: <9310211507.AA21025@slater.cem.msu.edu>
To: chemistry@ccl.net
Subject: vibrational calculation



There was a question about getting vibrational frequencies
by calculating points near the equilibrium geometry.

The answer is that you need at least three point to do a 
least squares fit to a quadratic, and this will work.

However, it is better to do more points (5-7) and then
a least squares fit to a morse potential or a higher order
polynomial.

If you're not sure how to get the frequency from this,
check the book "Molecular Vibrations" by Wilson, Decius and Cross.


				Dave Young
				young@slater.cem.msu.edu
				youngdc@msucem