Scaling Law for Kasha’s Rule in Photoexcited Molecular Aggregates

Holzinger R, Baßler NS, Ritsch H, Genes C (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Journal of Physical Chemistry A American Chemical Society

Book Volume: 128

Pages Range: 3910-3915

Issue: 19

DOI: 10.1021/acs.jpca.4c00342

Abstract

We study the photophysics of molecular aggregates from a quantum optics perspective, with emphasis on deriving scaling laws for the fast nonradiative relaxation of collective electronic excitations, referred to as Kasha’s rule. Aggregates exhibit an energetically broad manifold of collective states with delocalized electronic excitations originating from near-field dipole–dipole exchanges between neighboring monomers. Photoexcitation at optical wavelengths, much larger than the monomer–monomer average separation, addresses almost exclusively symmetric collective states, which for an arrangement known as H-aggregate show an upward hypsochromic shift. The extremely fast subsequent nonradiative relaxation via intramolecular vibrational modes populates lower energy, subradiant states, resulting in effective inhibition of fluorescence. Our analytical treatment allows for the derivation of an approximate scaling law of this relaxation process, linear in the number of available low-energy vibrational modes and directly proportional to the dipole–dipole interaction strength between neighboring monomers.

Additional Organisation(s)

Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa

Involved external institutions

Leopold-Franzens-Universität Innsbruck / University of Innsbruck AT Austria (AT) Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light DE Germany (DE)

How to cite

APA:

Holzinger, R., Baßler, N.S., Ritsch, H., & Genes, C. (2024). Scaling Law for Kasha’s Rule in Photoexcited Molecular Aggregates. Journal of Physical Chemistry A, 128, 3910-3915. https://doi.org/10.1021/acs.jpca.4c00342

MLA:

Holzinger, Raphael, et al. "Scaling Law for Kasha’s Rule in Photoexcited Molecular Aggregates." Journal of Physical Chemistry A 128 (2024): 3910-3915.

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