Excitation dynamics of acene molecules in weakly interacting environments

Media type: E-Book

Title: Excitation dynamics of acene molecules in weakly interacting environments

Contributor: Bohlen, Matthias [Verfasser]; Stienkemeier, Frank [Akademischer Betreuer]; Stienkemeier, Frank [Sonstige]; Issendorff, Bernd von [Sonstige]

Corporation: Albert-Ludwigs-Universität Freiburg, Fakultät für Mathematik und Physik ; Albert-Ludwigs-Universität Freiburg, Fakultät für Mathematik und Physik

imprint: Freiburg: Universität, 2023

Extent: Online-Ressource

Language: English

DOI: 10.6094/UNIFR/237591

Identifier:

Keywords: Cluster ; Silicium ; Dichtefunktionalformalismus ; Laserspektroskopie ; Molekülspektroskopie ; (local)doctoralThesis

Origination:

University thesis: Dissertation, Universität Freiburg, 2023

Footnote:

Description: Abstract: In this thesis, the dynamics of electronic excitation decays is investigated for three acene molecules, anthracene, tetracene, and pentacene, attached to the surface of solid argon clusters. It continues and extends previous studies on the excitation decay dynamics of the same molecules attached to neon clusters, aiming at a better understanding of the in- terplay of the molecule and the surface regarding the excitation dynamics. Laser-induced fluorescence spectra and excitation lifetimes of these molecules have been recorded with respect to cluster size, density of molecules, and excitation density. Particularly, for an- thracene on neon and argon clusters, a contrasting excitation lifetime behaviour is found. Also for tetracene and pentacene, a surprisingly strong dependence of the excitation decay dynamics with respect to the cluster material is found, although both neon and argon clusters are considered as weakly interacting environments. Several mechanisms are suggested to interpret the fundamentally different results for neon and argon clusters. Also with respect to the dopant density, qualitative differences of the excitation decay dynamics could be found. Based on the new experimental findings, assignments of col- lective radiative and non-radiative decay mechanism that made in previous studies are reassessed. As the dopant density, or the intermolecular distance, is a crucial quantity for the decay dynamics, a concise, analytical model is presented to relate the mean center- of-mass distance to the edge to edge distance distribution. Also, a significant dependence of the decay dynamics on the cluster size is found. Hence, the so-called titration method is assessed as a technique to determine mean cluster sizes at given expansion conditions. For small cluster sizes, the technique is found to deliver reasonable results, whereas for larger clusters, the technique seems to be not applicable any more

Access State: Open Access

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