CCL:G: About antiferromagnetic coupling



 Sent to CCL by: Serge Gorelsky [gorelsky,,gmail.com]
 > Dear CCLers:
 > Â 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 Âorbitals 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,
 Â Serge Gorelsky