TDDFT output question

Just Got Here

3:35:01 PM PST - Fri, Dec 30th 2011

Hi, all
The following is from my output of tddft calculation,

 Root  4 singlet a     0.047664078 a.u. (  1.2970061 eV)

 -------------------------------------------------------

    Transition Moments    X  0.64251   Y  0.44088   Z -0.33579

    Transition Moments   XX -6.00038  XY  4.27193  XZ  1.44530

    Transition Moments   YY  2.80721  YZ -1.45076  ZZ  2.02436

    Transition Moments  XXX 68.01522 XXY-37.76077 XXZ -9.39828

    Transition Moments  XYY 70.00061 XYZ 10.52811 XZZ  0.31881

    Transition Moments  YYY112.60149 YYZ -1.44061 YZZ 16.25681

    Transition Moments  ZZZ-28.04103

    Dipole Oscillator Strength                          0.02288

    Occ.214  a   ---  Virt.218  a    0.17724 X

    Occ.214  a   ---  Virt.219  a   -0.06488 X

    Occ.215  a   ---  Virt.218  a    0.65800 X

    Occ.215  a   ---  Virt.219  a    0.07690 X

    Occ.215  a   ---  Virt.220  a   -0.05800 X

    Occ.216  a   ---  Virt.218  a   -0.44676 X

    Occ.216  a   ---  Virt.219  a    0.22180 X

    Occ.217  a   ---  Virt.218  a    0.10449 X

    Occ.217  a   ---  Virt.219  a    0.45821 X

    Occ.217  a   ---  Virt.220  a    0.17993 X

    Occ.217  a   ---  Virt.221  a   -0.09552 X

My understanding is, in Root 4, it means, one electron in occupied state 214 is excited to virtual state 218, and so on.... But, why there are 3 transitions started from 215? There should be only 2 electrons in this occupied state. And why there are also more than 2 transitions arrive to the final state listed above.

Maybe my question sounds silly, but would anyone please teach me? Or tell me which book I should look into. Also, what does the last number mean in these lines? Transition moments related with each single excitation?

Thanks in advance.

Forum Regular

5:07:26 PM PST - Wed, Jan 4th 2012
Hi, It's not a silly question at all. Those are not 3 transitions from 215 but the dominant components of the transition vectors X and Y. Take a look at reviews by Casida on LR-TDDFT. Let me know if you need further clarification. Best regards, -Niri niri.govind@pnnl.gov

Guest -

7:59:30 AM PST - Wed, Feb 1st 2012
tddft
i am doing a single point in tddft, but the roots are disorder (i think). I am interested in the optically allowed transitions and i will add the the keyword SYMMETRY but i do not understand the keyword TARGETSYM; the manual say TARGETSYM must be specified when SYMMETRY is invoked" . Can someone help me?

Guest -

8:01:03 AM PST - Wed, Feb 1st 2012
sorry
I am Lex from Mexico alexpiedras@gmail.com regards

Guest -

10:37:15 AM PST - Wed, Feb 1st 2012
TRAGETSYM is defined in the manual just above the symmetry description. If you are going to limit the excitation space to a certain symmetry by setting the SYMMETRY keyword you need to specify the irreducible representation of the symmetry of state(s) you're interested in. For example A1g, T2g, etc. Hence, you need to know what the point group symmetry of your molecule is and the state symmetry label (you can look it up in a standard text book). Bert Quote: Feb 1st 2:59 pm i am doing a single point in tddft, but the roots are disorder (i think). I am interested in the optically allowed transitions and i will add the the keyword SYMMETRY but i do not understand the keyword TARGETSYM; the manual say TARGETSYM must be specified when SYMMETRY is invoked" . Can someone help me?

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