ERROR during the analysis of S0 population

[BITTU LAMA]

Dear Newton-X users,

I have been trying to compute the populations of the ground (S0) and excited states (S0-S10) of an organic chromophore. The analysis of the trajectories is providing the desired results for  the populations for the excited states, however for the ground state (S0) population, the value remains consistently at 0.0000 (mean_value) from 0-300 fs in all the trajectories. So can anyone please help me with the analysis of the S0 population? Is there a possibility that I overlook something during the preparation of the input?

Please kindly help me in this regard. 

Thank you so much. 

Regards

Ms. Bittu Lama

Research Scholar

Dept. of Chemistry

IIT Guwahati, Assam

781039-India

[Krishnandu Dey]

Ms Lama,

Did you look at the trajectory diagrams by doing $NX/plot in RESULTS directory in each TRAJn? If you find any hoppings taking place it should reflect in the mean_value file upon analysis run. If there's any hopping taking place , and mean_value is not showing any result in ground state, kindly look again into the input file for analysis run. Any hoppings into the ground state must always if not an exception will show up on mean_value file. A sample trajectory would be nice to see. 

Cheers...

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[BITTU LAMA]

Dear  Krishnandu,

Thank you for your kind response. Yes, I plotted the energies of all the states, and since I have performed TDDFT non-adiabatic dynamics, where the trajectories were run for 300 fs or until a crossing with the S0 state (within 0.15 eV) was reached, the trajectories terminates at a particular time when the S1/S0 gap reduces to 0.15eV. Though the trajectory terminates when the energy gap between S1/S0 reduces to 0.15 eV and no hopping between these states takes place, how would it be possible to get the S0 population as observed in Phys. Chem. Chem. Phys., 2015, 17, 7787--7799. 

Thanks again.

Regards 

Ms. Bittu Lama

[Krishnandu Dey]

Miss Bittu,

As you state the problem , my best guess would be that there must have been some options set during the input file generation where it was told to terminate upon reaching  close to 0.15eV. However I won’t jump into conclusions and since I do dynamics using Columbus package it is beyond my understanding. I shall look tomorrow and let you know the results by going through the NewtonX manual. 

Cheers!

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[Lischka, Hans]

Hi Bittu,

You cannot get a population of S0 because the program will stop when the 0.15 eV limit to the ground state is reached. TDDFT cannot deal with the S1/S0 crossing and therefore the procedure is to stop the dynamics at that point. This is explained in some NX papers, but I do not have any reference at hand.

Best regards, Hans

 

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[BITTU LAMA]

Dear  Krishnandu and Prof.  Lischka,

Thank you so much for your kind help. 

Regards 

Ms. Bittu Lama

[Krishnandu Dey]

Ms Lama,

Apologies for not being much of help. If such problem persists you could try other methods apart from tddft. In my case MCSCF calculation helped. 

Cheers!

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