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Photoexcitation of Ge9$^{-}$ Clusters in THF: New Insights into the Ultrafast Relaxation Dynamics and the Influence of the Cation

Michenfelder, Nadine C.; Gienger, Christian; Dilanas, Melina; Schnepf, Andreas; Unterreiner, Andreas-Neil

Abstract:
We present a comprehensive femtosecond (fs) transient absorption study of the [Ge$_{9}$(Hyp)$_{3}$]$^{-}$ (Hyp = Si(SiMe3)3) cluster solvated in tetrahydrofuran (THF) with special emphasis on intra- and intermolecular charge transfer mechanisms which can be tuned by exchange of the counterion and by dimerization of the cluster. The examination of the visible and the near infrared (NIR) spectral range reveals four different processes of cluster dynamics after UV (267/258 nm) photoexcitation related to charge transfer to solvent and localized excited states in the cluster. The resulting transient absorption is mainly observed in the NIR region. In the UV-Vis range transient absorption of the (neutral) cluster core with similar dynamics can be observed. By transferring concepts of: (i) charge transfer to the solvent known from solvated Na$^{-}$ in THF and (ii) charge transfer in bulk-like materials on metalloid cluster systems containing [Ge$_{9}$(Hyp)$_{3}$]$^{-}$ moieties, we can nicely interpret the experimental findings for the different compounds. The first process occurs on a fs timescale and is attributed to localization of the excited electron in the quasi-conduction band/excited state which competes with a charge transfer to the solvent. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000123964
Veröffentlicht am 24.09.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Physikalische Chemie (IPC)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1420-3049
KITopen-ID: 1000123964
Erschienen in Molecules
Band 25
Heft 11
Seiten Art.Nr. 2639
Vorab online veröffentlicht am 05.06.2020
Schlagwörter ultrafast dynamics; metalloid cluster; germanium; photoexcitation; excess charge
Nachgewiesen in Scopus
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