From owner-chemistry@ccl.net Wed Mar 31 10:53:00 2010
From: "Anton Nizovtsev nanto[A]mail.ru" <owner-chemistry^-^server.ccl.net>
To: CCL
Subject: CCL:G: Oscillator strength
Message-Id: <-41560-100331105044-7870-KIOz1CjwtzHKBtg7Z07rEw^-^server.ccl.net>
X-Original-From: "Anton  Nizovtsev" <nanto]-[mail.ru>
Date: Wed, 31 Mar 2010 10:50:35 -0400


Sent to CCL by: "Anton  Nizovtsev" [nanto-$-mail.ru]
Thank you for response!
I am interesting in singlet-singlet transition from A(S0)B(S0) to A*(T1)B*(T1). This case seems to be not trivial. The question is to calculate oscillator strength of such transition. Id like to know your opinion about applicability of linear response methods (namely, TDDFT, CCn etc.) and other possible methods to my problem.  


Thanks in advance
Anton



> "Alexander Bagaturyants bagaturyants%x%gmail.com"  wrote:
> 
> Sent to CCL by: "Alexander Bagaturyants" [bagaturyants a gmail.com]
> Dear Anton,
> The answer depends on what you mean under "simultaneous S0-T1 transitions of
> each molecular fragment". If you consider that the transition in the complex
> must be a linear combination of states like A*(T1)B(S0) + A(S0)B*(T1) or A*B
> - AB*, this is one thing; to calculate such a state, you should just
> consider your complex in the same way as an isolated component. I believe
> that the transition energy in the complex will be almost the same as in the
> isolated component, and the two states (A*B + AB* or A*B - AB*) will be near
> degenerate. The state will have the T1 symmetry. However, if you is
> interested in the state that corresponds to the simultaneous S0-T1
> transition in both components, you must consider the state A*(T1)B*(T1),
> which is somewhat more complicated. First, the energy of this state must be
> about twice as large as the energy of the transition in the isolated
> component. So you must consider many excited states in order to locate the
> desired energy range. Next, you will get three different spin states (again,
> near degenerate) for such a configuration, singlet, triplet, and quintet.  
> You may use any available QC program, like free GAMESS, Orca, etc., or
> commercial Gaussian, Turbomole, etc.
> Happy calculations
> Best regards,
> 
> Prof. Alexander A. Bagatur'yants
> Photochemistry Center
> Russian Academy of Sciences
> ul. Novatorov 7a
> Moscow 119421 Russia
> Phone:  +7(495)9362588 (office)
>         +7(916)5317022 (mobile)
> Fax:    +7(495)9361255
> e-mail: sasha],[photonics.ru 
>         bagaturyants],[gmail.com
> 
> 
> -----Original Message-----
> > From: owner-chemistry+sasha==photonics.ru],[ccl.net
> [mailto:owner-chemistry+sasha==photonics.ru],[ccl.net] On Behalf Of Anton
> Nizovtsev nanto#,#mail.ru
> Sent: Monday, March 29, 2010 2:47 PM
> To: Bagaturyants, Alexander A. 
> Subject: CCL: Oscillator strength
> 
> 
> Sent to CCL by: "Anton  Nizovtsev" [nanto^-^mail.ru]
> 
> Suppose there are two molecules in its singlet ground states separated at
> several angstroms (5, for example). I want to calculate excitation energy
> and oscillator strength for transition between ground state of such complex
> and excited state corresponding simultaneous S0-T1 transitions of each
> molecular fragment. Is it possible to perform? Which methods are suitable
> for this problem in quantum chemical programs?
> 
> Thanks in advance
> Anton
> 
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