Request for Assistance with Perylene Diimide System Analysis Using SHARC-LVC Method

[lukhman9020]

Dear Sir,

I am currently working on a perylene diimide system where the molecule does not exhibit emission. Upon exciting the molecule into the S2 and S3 states, I observed that it decays and populates a long-lived species with a decay time on the picosecond timescale. I have confirmed the long-lived nature of this species through femtosecond Transient Absorption Spectroscopy (TAS). However, during nanosecond TAS, I observed a very low triplet population, which leads me to suspect that this long-lived species could be an Intramolecular Charge-Transfer (ICT) state. I believe this state may be present in the S1 state, as the decay time of the S2 and S3 states falls within the picosecond timescale, which aligns with the internal conversion in the singlet state. This is my hypothesis, but I have been unable to prove it theoretically.

I performed a TheoDORE analysis on the ground state optimized structure, but I did not obtain significant charge-transfer (CT) values. Therefore, I am considering simulating the same decay time observed experimentally using the SHARC-LVC method. My plan is to optimize the crossing point structure between the S2 and S1 states and perform TheoDORE analysis for this crossing point structure. Would this approach be effective, or should I apply TheoDORE analysis throughout the SHARC-LVC calculation? Additionally, I am uncertain if I can obtain a plot showing the population of the CT state in S1 using the SHARC-LVC method.

Could you please help me to solve this issue? Please help me.

Best regards, LUKHMANUL HAKEEM K