From owner-chemistry@ccl.net Tue Mar 12 09:25:00 2013
From: "matthew v sheridan mvsherid:-:uvm.edu" <owner-chemistry###server.ccl.net>
To: CCL
Subject: CCL: Unrestricted Formalism
Message-Id: <-48403-130312082932-32702-+Cd4xDuZE8wHYfPPmfrvAA###server.ccl.net>
X-Original-From: "matthew v sheridan" <mvsherid]^[uvm.edu>
Date: Tue, 12 Mar 2013 08:29:31 -0400


Sent to CCL by: "matthew v sheridan" [mvsherid~!~uvm.edu]
Hi CCL,

For a number of calculations on open-shell systems the SOMO is often not the HOMO using the unrestricted formalism. This has been brought up a few times before on CCL and it seems that it is agreed to be an acceptable output.  I was wondering why that is if it isn't accurately describing the MO picture of the system? 


Pople et al. Int. J. Quantum Chem. 1995, 56, 303-305. "Spin-Unrestricted Character of Kohn-Sham Orbitals for Open-Shell Systems"
&
Ohta, J. Mol. Struct. (Theochem) 2002, 587, 33-41. "A handy way to find radical orbitals buried in UHF wavefunctions"

Thank you,
Matt S.

mvsherid%a%uvm.edu