Subject: RE: force constants of diatomics in GAUSSIAN-03

From: "Xavier ASSFELD" <Xavier.Assfeld<<at>>lctn.uhp-nancy.fr>
Date: Mon, 26 Jul 2004 10:29:17 +0200

X> -----Message d'origine-----
X> De : Computational Chemistry List [mailto:chemistry-request<<at>>ccl.net]De
X> la part de Shobe, David
X> Envoyi : jeu. 22 juillet 2004 15:57
X> @ : chemistry<<at>>ccl.net
X> Objet : CCL:force constants of diatomics in GAUSSIAN-03
X>
--cut--
X>
X> 2. But if that's true, why is R>2 for CO and NO?
X>
--cut--

Hello,

ain't it simply related to the level of theory ? I mean, the force constant
is the second derivative of the total electronic energy with respect to the
nuclear coordinates, hence force constant are functions of the level of
theory. If the level corresponds to the exact solution of the schrvdinger
equation then the ratio would be lower than 2 !?
Just my 2 eurocents...

                                      ...Xav

Pr. Xavier Assfeld                  Xavier.Assfeld<<at>>lctn.uhp-nancy.fr
Laboratoire de Chimie thiorique     (T) 33 3 83 68 43 82
Universiti Henri Poincari           (F) 33 3 83 68 43 71
F-54506 Nancy B.P. 239              http://www.lctn.uhp-nancy.fr