From chemistry-request # - at - # server.ccl.net Tue Jul 9 19:49:44 2002 Received: from smtp.laposte.net ([213.30.181.7]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g69Nnhp21254 for ; Tue, 9 Jul 2002 19:49:43 -0400 Received: from nouveaupc (217.128.255.253) by smtp.laposte.net (6.0.053) id 3D2A2BF000014E06 for chemistry -8 at 8- ccl.net; Wed, 10 Jul 2002 01:48:36 +0200 Message-ID: <001601c227a3$1db021f0$3b96fea9;at;nouveaupc> From: "Alexandre Hocquet" To: Subject: CHELPG and AIM Date: Wed, 10 Jul 2002 01:48:24 +0200 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01C227B3.E093FF60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 This is a multi-part message in MIME format. ------=_NextPart_000_0013_01C227B3.E093FF60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable > one-center overlap integrals). Like most such schemes, it is an = arbitrary > scheme for assigning charges (since "atomic charges" are not = unambiguously > defined, at least outside of Bader's AIM theory). I would say, like ALL schemes, be they inside or outside Bader's AIM = theory. Atomic charges are just impossible to define as a physical observable. People may stick the word "rigorous" in front ot their theories if this = make them feel better. Bader's AIM theory is a wonderful and useful tool, the kind that you can extract a lot of chemical insight out of it, but its definition of = charge is only one among the others, with its strengths, weaknesses and = ambiguities. ------------------------------------------------------------ Alexandre HOCQUET Laboratoire de Physicochimie Biomol=E9culaire et Cellulaire UMR CNRS 7033 hocquet.,at,.ccr.jussieu.fr Fax: 33 1 44277560 LPBC, case courrier 138 4 Place Jussieu, 75252 PARIS Cedex 05 France ------------------------------------------------------------ ------=_NextPart_000_0013_01C227B3.E093FF60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
> one-center=20 overlap integrals). Like most such schemes, it is an arbitrary
> = scheme=20 for assigning charges (since "atomic charges" are not = unambiguously
>=20 defined, at least outside of Bader's AIM theory).

I would say, = like ALL=20 schemes, be they inside or outside Bader's AIM theory.
Atomic charges = are=20 just impossible to define as a physical observable.
People may stick = the word=20 "rigorous" in front ot their theories if this make
them feel=20 better.
Bader's AIM theory is a wonderful and useful tool, the kind = that you=20 can
extract a lot of chemical insight out of it, but its definition = of charge=20 is
only one among the others, with its strengths, weaknesses and=20 ambiguities.
---------------------------------------------------------= ---
Alexandre=20 HOCQUET
Laboratoire de Physicochimie Biomol=E9culaire et = Cellulaire
UMR CNRS=20 7033
hocquet _-at-_)ccr.jussieu.fr
Fax: 33 1 44277560
LPBC, case = courrier 138
4=20 Place Jussieu, 75252 PARIS Cedex 05=20 France
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