SKM 2021 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Molecular Electronics, Hybrid and Perovskite Photovoltaics

CPP 13.5: Talk

Friday, October 1, 2021, 11:30–11:45, H3

Optimally-tuned range-separated hybrid functionals for accurate molecular excited-state geometries — •Bernhard Kretz and David A. Egger — Technical University of Munich, Germany

Molecular excited-state (ES) potential energy surfaces (PES) obtained by computational methods can shed light on reaction mechanisms and pathways in photocatalytic reactions. These ES PES can be calculated using either time-dependent density functional theory (TD-DFT) or high-level wave-function methods. TD-DFT based calculations are computationally very efficient, but often lack the accuracy achieved by computationally more expensive wave-function methods[1]. Recently, the class of optimally-tuned range-separated hybrid (OT-RSH) functionals[2] was developed which promises to reduce the gap in accuracy.

In our recent work[3], by comparison with high accuracy wave-function data from literature, we assessed the accuracy of TD-DFT and OT-RSH for the excited-state geometries for a selection of organic molecules with varying complexity of their ES PES. We mainly focused on the structural parameters of the lowest-excited singlet states. Our results show that OT-RSH maintains the accuracy of conventional functionals for small molecules, while it improves the description of more complex ES PESs involving charge-transfer states.

[1] C. Azarias, J. Phys. Chem. A, 121, 32, 6122 (2017)

[2] L. Kronik et al., J. Chem. Theory Comput., 8, 5, 1515 (2012)

[3] B. Kretz and D. A. Egger, J. Chem. Theory Comput., 17, 1, 357 (2021)