From owner-chemistry@ccl.net Wed Mar 30 12:44:00 2011
From: "Serge Gorelsky gorelsky _ gmail.com" <owner-chemistry]*[server.ccl.net>
To: CCL
Subject: CCL:G: About antiferromagnetic coupling
Message-Id: <-44246-110330122434-19864-djpA+acKU4skj8alUb10wA]*[server.ccl.net>
X-Original-From: Serge Gorelsky <gorelsky!=!gmail.com>
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Date: Wed, 30 Mar 2011 12:24:26 -0400
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Sent to CCL by: Serge Gorelsky [gorelsky,,gmail.com]
> Dear CCLers:
>   I'm new to Gaussian,so I try to reproduce some example at Gaussian's
> website.But I'm confused about one.In the "Antiferromagnetic coupling"
> example of gauss03--www.gaussian.com/g_tech/antiferr_g03.htm--it tries to
> reorder the orbitals,and choose some  orbitals changed to .What I'm
> confused is the criterion that it choose the orbitals to be reordered.Why they choose these orbitals to be reordered.

yes, that's indeed a confusing method. A much better (simpler and 100%
reliable) method is to take fragment orbitals and generate an
appropriate guess wavefunction. See Appendix II of the AOMix manual
(http://www.sg-chem.net/aomix/AOMix-manual.pdf) for details.
-- 
Best regards,
  Serge Gorelsky