CCL: Question on calculation of charge center of electrons in a molecule

From: Ulf Ekström <ulfek]^[few.vu.nl>
Subject: CCL: Question on calculation of charge center of electrons in a molecule
Date: Thu, 25 Nov 2010 17:58:25 +0100

 Sent to CCL by: =?ISO-8859-1?Q?Ulf_Ekstr=F6m?= [ulfek],[few.vu.nl]
 On Thu, Nov 25, 2010 at 9:56 AM, Herbert Fruchtl
 herbert.fruchtl-.-st-andrews.ac.uk <owner-chemistry .. ccl.net> wrote:
 >
 > Sent to CCL by: Herbert Fruchtl [herbert.fruchtl*_*st-andrews.ac.uk]
 > I don't have time to look at the maths of it, but I think the centre of
 > charge of the electron density should be identical to the centre of the
 > Mulliken charges, which would be easy to calculate (analogous to the centre
 > of mass).
 This will not work, for example if you have a single centre basis set all
 Mulliken charge would be on that center. What you should do is to compute
 the dipole moment of the molecule and use that to work out the center
 of charge.
 Sincerely,
 Ulf Ekstrom