Mariana T. do Casal
KU Leuven, Belgium

Light is at the heart of many critical processes, from OLED design to photosynthesis. Common among all those fields is that an excited molecule must release energy to return to the ground
state. However, deciphering how molecules release this energy is not trivial. It involves identifying all the possible competing deactivation pathways, the electronic structure character
of the relevant states and how the excited-state decay rates dictate the system's fate. To advance light-related applications, we must map these possibilities.

In the first part of this talk, I will discuss how to evaluate excited-state rate constants of organic fluorophores using Fermi’s golden rule. In such a static approach, only a few key points of the
potential energy surfaces, where radiative, internal conversion and intersystem crossing rates can be evaluated. Here, the limitations and approximations of the vibronic calculations are crucial
to reaching a semi-quantitative estimate, where I will show examples of successful and challenging cases. In the second part of this talk, I will show how one can take advantage of cheap
wavefunction descriptors to obtain insight into the most likely deactivation pathways and guide the design of new emitters.

References:

1. M. T. do Casal,* Y. Badawy, D. Escudero* Modelling MR-TADF emitters: Excited-state decay rate constants and wavefunction descriptors. J. Phys. Chem. C, 2023, 128:18170.
2. M. T. do Casal, K. Veys, M. Bousquet, D. Escudero,* D. Jacquemin,* First-principles calculations of excited-state decay rates constants in organic fluorophores, J. Phys. Chem. A,2023, 127:10033.