RE: force constants of diatomics in GAUSSIAN-03

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>  "-at-"  : 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