From owner-chemistry@ccl.net Sat Aug 6 09:41:00 2011 From: "Eli Lam eli_lsh:yahoo.com.hk" To: CCL Subject: CCL:G: transition dipole moment Message-Id: <-45215-110806091613-12628-oZBUyPv8/vM20EafaGSO5A(-)server.ccl.net> X-Original-From: "Eli Lam" Date: Sat, 6 Aug 2011 09:16:10 -0400 Sent to CCL by: "Eli Lam" [eli_lsh..yahoo.com.hk] Dear Jens, Thank you so much for your help! But I still have some queries.. 1) I've been trying to calculate the transition dipole moment using Gaussian03 with TDDFT calculations, but all have vanish to zero in the Singlet to Triplet excited states. I understand that it is a spin-forbidden transition and thus yielding zeros. However, is there any other ways to calculate the transition dipole moment for the Triplet excited states? 2) Actually I'm curious if this transition probability can give any hints to the emission intensity of a molecule? I've read some papers* that the transition dipole moment can give information to the phosphorescence rate, but would it be possible to give information to the radiative intensity of molecules? Thank you so much! Eli *1)Phys. Chem. Chem. Phys., 2009, 11, 1688-1896 2)J. Chem. Phys, 124, 124101 (2006) ------------------------ > "Jens Spanget-Larsen spanget]_[ruc.dk" wrote: > > Sent to CCL by: Jens Spanget-Larsen [spanget+*+ruc.dk] > This is a multi-part message in MIME format. > --------------050400030504050601070501 > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > Content-Transfer-Encoding: 7bit > > > Dear Eli! > The transition dipole moment is not equal to the difference between > ground and excited state dipole moments. The electronic transition > dipole moment is an integral defined as M(i,f) = , where > W(i) and W(f) are the electronic wavefunctions for the initial and final > state, and m is the electric dipole moment operator, m = {mx,my,mz}. The > transition dipole moment is a vector, and the direction of the vector is > called the polarization direction of the transition. The transition > probability is proportional to the square of the length of the vector > (more precisely: proportional to the square of the projection onto the > electric vector of the electromagnetic radiation field, but in isotropic > media, the directional dependence is averaged over all orientations). - > When you perform a Gaussian03 CIS or TD calculation, the x, y, and > z-components of the transition moments for the calculated electronic > transitions are printed under the heading "Ground to excited state > transition electric dipole moments (Au)". > Yours, Jens >--< > > ------------------------------------------------------ > JENS SPANGET-LARSEN Office: +45 4674 2710 > Dept. of Science (18.1) Fax: +45 4674 3011 > Roskilde University Mobile: +45 2320 6246 > P.O.Box 260 E-Mail: spanget^_^ruc.dk > DK-4000 Roskilde, Denmark http://www.ruc.dk/~spanget > ------------------------------------------------------ > > > On 8/4/2011 18:02, Eli Lam eli_lsh()yahoo.com.hk wrote: > > Sent to CCL by: "Eli Lam" [eli_lsh,yahoo.com.hk] > > Hi CCLers, > > > > I have some queries to the basic of transition dipole moment and would like to ask what exactly is > > transition dipole moment? Is it equalled to the dipole moment difference between the ground state > > and the excited state of a molecule? Or how to calculate it using gaussian03 package? And is it > > related to the probability of the transition to a particular excited state? > > > > Thank you so much! > > Eli> > > > > --------------050400030504050601070501 > Content-Type: text/html; charset=ISO-8859-1 > Content-Transfer-Encoding: 7bit > > > > > http-equiv="Content-Type"> > > > >
> Dear Eli!
> The transition dipole moment is not equal to the difference > between ground and excited state dipole moments. The electronic > transition dipole moment is an integral defined as M(i,f) = > <W(i)|m|W(f)>, where W(i) and W(f) are the electronic > wavefunctions for the initial and final state, and m is the > electric dipole moment operator, m = {mx,my,mz}. The transition > dipole moment is a vector, and the direction of the vector is > called the polarization direction of the transition. The > transition probability is proportional to the square of the > length of the vector (more precisely: proportional to the square > of the projection onto the electric vector of the > electromagnetic radiation field, but in isotropic media, the > directional dependence is averaged over all orientations). - > When you perform a Gaussian03 CIS or TD calculation, the x, y, > and z-components of the transition moments for the calculated > electronic transitions are printed under the heading "Ground to > excited state transition electric dipole moments (Au)".
> Yours, Jens >--<
> > 
  -----------------------------------------------
-------
>   JENS SPANGET-LARSEN         Office:      +45 4674 2710
>   Dept. of Science (18.1)     Fax:         +45 4674 3011
>   Roskilde University         Mobile:      +45 2320 6246
>   P.O.Box 260                 E-Mail:     spanget^_^ruc.dk
>   DK-4000 Roskilde, Denmark   http://www.ruc.dk/~spanget
>   ------------------------------------------------------
>
> On 8/4/2011 18:02, Eli Lam eli_lsh()yahoo.com.hk wrote: >
cite="mid:-id%233dt-45205-110804120226-26489-oaST1ZfkIX5ERrKFo8gb9g^_^server.ccl.net" > type="cite"> > 
Sent to CCL by: "Eli  Lam" [eli_lsh,yahoo.com.hk]
> Hi CCLers, 
> 
> I have some queries to the basic of transition dipole moment and would like to ask what exactly is 
> transition dipole moment?  Is it equalled to the dipole moment difference between the ground state 
> and the excited state of a molecule?  Or how to calculate it using gaussian03 package?  And is it 
> related to the probability of the transition to a particular excited state?
> 
> Thank you so much!
> EliE-mail to subscribers: CHEMISTRY^_^ccl.net or use:
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> > > > --------------050400030504050601070501-- > >