Siddheshwar Chopra
sidhusai@gmail.com
Regards,
On Thu Sep 11 '14 5:40pm, Pavlo Solntsev wrote
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>On Thu Sep 11 '14 7:21am, Siddheshwar Chopra wrote
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>>Dear Firefly Users,
>>I am stuck up with the concept of excited states. Specifically speaking with some doubts in TDDFT.
>>What is meant by NSTATE in FIREFLY i/p file?
>The number of states to be found, excluding the ground state. (Default is 1)
>>I know ISTATE is singlet or doublet...
>The state for which properties and/or the gradient will be calculated. Only one state
>can be chosen. A negative sign may precede the state number; this will enable state
>tracking for the state of interest. (Default is 1)
>When I read the firefly TDDFT o/p file.. I see that for every EXCITED STATE, I have a set of probable transitions... THIS IS WHAT IS CONFUSING ME ...
>What do expect? To see a pure transition from an orbital A to an orbital B? You always have a "contribution" from other transitions. Lets calla them micro-transition. If you have a system where single determinant approach works fine, you should be able to see major component with expansion coefficients close to 0.9.
>>What I assumed till now is that first excited state is LUMO. But now in the firefly o/p file I see HOMO--> LUMO transitions occuring for almost all excited states 1,2,3 etc..
>What about expansion coefficients? Are they the same for all states? If so, you probably have multireference character.
>>So my concept of Excited state is unclear... I just open the TDDFT o/p fie with Gausssum and get the spectra.
>I also get the probabilities of the particular transitions alongwith their osc. strengths. Probabilities must be calculated by squaring and adding the SAPs. But I can't visualize the excited state here. Please explain to me this.
>FF prints all components for transition dipole moment. What does it meant to visualize excited state?
>Also, it would be useful to see the output file.
>Sincerely,
>Pavlo.
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>>Kind Regards,