From owner-chemistry ^%at%^ ccl.net Wed Aug 17 11:33:00 2016 From: "Pierre Archirel pierre.archirel{:}u-psud.fr" To: CCL Subject: CCL:G: triplet TDDFT calculation Message-Id: <-52346-160817104130-21698-P7cz9bi6aJyZgsJGNef+sw/a\server.ccl.net> X-Original-From: Pierre Archirel Content-Type: multipart/alternative; boundary="------------B5BFC892BE39EB7B9D1B3D20" Date: Wed, 17 Aug 2016 16:41:18 +0200 MIME-Version: 1.0 Sent to CCL by: Pierre Archirel [pierre.archirel[*]u-psud.fr] This is a multi-part message in MIME format. --------------B5BFC892BE39EB7B9D1B3D20 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Dear colleagues, This is an answer to Michael Morgan. I have used with success a somewhat rough and clumsy method for limiting spin contamination in excited states. You will find it in: P. Archirel et al. J. Phys. Chem. B 2015, 119, 5282−5298 I hope this will help, Best wishes, Pierre Archirel, LCP, Universite Paris-Sud, Orsay France > > Dear All, > > Standard TDDFT calculations calculate singlet->singlet excitations. In > Gaussian, I can see that for each excitation, =0.000. > > While I calculate molecules like O2 which the ground state is triplet, > I need calculate triplet->triplet excitations by assigning TD=triplet . > In output, I found all kinds of values (from 2 to 4). I am > confused: for those are not close to 3, are they still spin-allowed > therefore > experimentally observable? Should I include them if I want to predict > an absorption spectrum for the molecule? > > Thank you very much! > > Michael > -- ______________________________________________________________ Pierre Archirel Groupe Théosim: Théorie et Simulation Laboratoire de Chimie Physique Tel: 01 69 15 63 86 Bât 349 Fax: 01 69 15 61 88 91405 Orsay Cédex France pierre.archirel/./u-psud.fr ______________________________________________________________ --------------B5BFC892BE39EB7B9D1B3D20 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

Dear colleagues,
This is an answer to Michael Morgan.
I have used with success a somewhat rough and clumsy method for limiting spin contamination in excited states.
You will find it in:
P. Archirel et al. J. Phys. Chem. B 2015, 119, 5282−5298
I hope this will help,
Best wishes,
Pierre Archirel, LCP, Universite Paris-Sud, Orsay France

Dear All,

Standard TDDFT calculations calculate singlet->singlet excitations. In Gaussian, I can see that for each excitation, <S**2>=0.000.

While I calculate molecules like O2 which the ground state is triplet, I need calculate triplet->triplet excitations by assigning TD=triplet .
In output, I found all kinds of <S**2> values (from 2 to 4). I am confused: for those are not close to 3, are they still spin-allowed therefore
experimentally observable? Should I include them if I want to predict an absorption spectrum for the molecule?

Thank you very much!

Michael

-- 

______________________________________________________________

 Pierre Archirel
 Groupe Théosim: Théorie et Simulation
 Laboratoire de Chimie Physique      Tel: 01 69 15 63 86
 Bât 349                             Fax: 01 69 15 61 88
 91405 Orsay Cédex
 France                   pierre.archirel/./u-psud.fr
______________________________________________________________

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