[molpro-user] center of charge orientation

[Jacky LIEVIN]

Dear Somnath,

The origin used in your calculation is the centre of the nuclear charges. You can easily check from the cartesian coordinates that the nuclear contribution to the dipole moment vanishes at origin.
In order to take the electronic contribution into account, you should calculate a wave function corresponding to the anionic system. The geometry at which the dipole moment vanishes will  change with the method of calculation (HF, CASSCF, … and basis set), and of course you cannot predict it before having performed the calculation.
If you really want to put the origin at the centre of charge of the whole system (maybe for calculating other origin dependent properties) you could probably recalculate the coordinates of the origin on the basis of the nuclear and electronic dipole moment values. The "property" command should help you.

yours

Jacky


Le 19 sept. 2014 à 18:16, Somnath BHOWMICK <somnath.bhowmick at etu.univ-amu.fr> a écrit :

> Dear Molpro Users,
> 
> I am trying to calculate CASSCF energies for an anionic H2+F- system. I am orienting the system such that the origin is set at the center of charge.  At this origin, the dipole moment of the system should vanish. However, the dipole moment obtained in HF and corresponding CASSCF calculation is not zero, and is quite high. 
> Any suggestions?
> 
> I am attaching the output of my calculation with this mail.
> 
> Thanks in advance.
> 
> Somnath Bhowmick
> 
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Prof. Jacky Liévin
Service de Chimie Quantique et Photophysique
Université Libre de Bruxelles, CPi 160/09
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Tel: +32-2-650 4089
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