From owner-chemistry@ccl.net Mon Jan  9 12:47:00 2012
From: "jacqueline cawthray jcawth01,,gmail.com" <owner-chemistry!=!server.ccl.net>
To: CCL
Subject: CCL: Clarification for restricted/unrestricted spin in TDDFT
Message-Id: <-46124-120109124606-22212-/vR4robuXdGjEygBcI0W0Q!=!server.ccl.net>
X-Original-From: "jacqueline  cawthray" <jcawth01()gmail.com>
Date: Mon, 9 Jan 2012 12:46:04 -0500


Sent to CCL by: "jacqueline  cawthray" [jcawth01_+_gmail.com]
Hi

I'm trying to calculate the UV spectra of some transition metal complexes 
involving Cu2+, Fe3+ and Zn2+. I have successfully been able to calculate Zn2+ 
complexes which show good agreement with experimental results. However I am 
not having much luck with Cu2+ or Fe3+. I understand I may need to change 
basis sets (I have been using B3LYP/6-31+g(d,p) and am currently trying with 
LanL2Dz on the metal) but have read about using unrestricted B3LYP. Can 
someone possibly explain (in laymans terms) what the difference between 
restricted and unrestricted is so I can decide which to use?

Thanks
Jacquie