Timing the Escape of a Caged Electron

Connor Fields; Aleksandra Foerster; Sadegh Ghaderzadeh; Ilya Popov; Bang Huynh; Filipe Junqueira; Tyler James; Sofia Alonso Perez; David A Duncan; Tien-Lin Lee; Yitao Wang; Sally Bloodworth; Gabriela Hoffman; Mark Walkey; Richard J Whitby; Malcolm H Levitt; Brian Kiraly; James N O'Shea; Elena Besley; Philip Moriarty

arXiv · 2504.06733

Timing the Escape of a Caged Electron

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Abstract

Charge transfer is fundamentally dependent on the overlap of the orbitals comprising the transport pathway. This has key implications for molecular, nanoscale, and quantum technologies, for which delocalization (and decoherence) rates are essential figures of merit. Here, we apply the core hole clock technique - an energy-domain variant of ultrafast spectroscopy - to probe the delocalization of a photoexcited electron inside a closed molecular cage, namely the Ar 2p54s1 state of Ar@C60. Despite marginal frontier orbital mixing in the ground configuration, almost 80% of the excited state density is found outside the buckyball due to the formation of a markedly diffuse hybrid orbital. Far from isolating the intracage excitation, the surrounding fullerene is instead a remarkably efficient conduit for electron transfer: we measure characteristic delocalization times of 6.6 $\pm$ 0.3 fs and $\lesssim$ 500 attoseconds, respectively, for a 3D Ar@C60 film and a 2D monolayer on Ag(111).

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Connor Fields, Aleksandra Foerster, Sadegh Ghaderzadeh, Ilya Popov, Bang Huynh, Filipe Junqueira, Tyler James, Sofia Alonso Perez, David A Duncan, Tien-Lin Lee, Yitao Wang, Sally Bloodworth, Gabriela Hoffman, Mark Walkey, Richard J Whitby, Malcolm H Levitt, Brian Kiraly, James N O'Shea, Elena Besley, Philip Moriarty. 2025-04-09. Timing the Escape of a Caged Electron. https://arxiv.org/abs/2504.06733

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