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Nonradiative decay and absorption rates of quantum emitters embedded in metallic systems: Microscopic description and their determination from electronic transport
摘要： We investigate nonradiative decay and absorption rates of two-level quantum emitters embedded in a metal at low temperatures. We obtain the expressions for both nonradiative transition rates and identify a unique, experimentally accessible way to obtain both nonradiative transition rates via electronic transport in the host metallic system. Our findings not only provide a microscopic description of the nonradiative channels in metals, but they also allow one to identify, determine, and differentiate them from other decay channels, which is crucial to the understanding and controlling of the light-matter interactions at the nanoscale.
关键词： nonradiative decay,metallic systems,quantum emitters,electronic transport,absorption rates
更新于2025-09-23 15:21:21
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Electronic State and Photophysics of 2-Ethylhexyl-4-methoxycinnamate as UV-B Sunscreen under Jet-Cooled Condition
摘要： The title compound, 2-ethylhexyl-4-methoxycinnamate (2EH4MC), is known as a typical ingredient of sunscreen cosmetics that effectively converts the absorbed UV-B light to thermal energy. This energy conversion process includes the nonradiative decay (NRD): trans?cis isomerization and finally going back to the original structure with a release of thermal energy. In this study, we performed UV spectroscopy for jet-cooled 2EH4MC to investigate the electronic/geometrical structures as well as the NRD mechanism. Laser-induced-fluorescence (LIF) spectroscopy gave the well-resolved vibronic structure of the S1?S0 transition; UV?UV hole-burning (HB) spectroscopy and density functional theory (DFT) calculations revealed the presence of syn and anti isomers, where the methoxy (?OCH3) groups orient in opposite directions to each other. Picosecond UV?UV pump?probe spectroscopy revealed the NRD process from the excited singlet (S1 (1ππ*)) state occurs at a rate constant of ～1010?1011 s?1, attributed to internal conversion (IC) to the 1nπ* state. Nanosecond UV?deep UV (DUV) pump?probe spectroscopy identified a transient triplet (T1 (3ππ*)) state, whose energy (from S0) and lifetime are 18 400 cm?1 and 20 ns, respectively. These results demonstrate that the photoisomerization of 2EH4MC includes multistep internal conversions and intersystem crossings, described as "S1 (trans, 1ππ*) → 1nπ* → T1 (3ππ*) → S0 (cis)".
关键词： nonradiative decay,photophysics,DFT calculations,trans?cis isomerization,jet-cooled spectroscopy,2-ethylhexyl-4-methoxycinnamate,UV-B sunscreen
更新于2025-09-19 17:13:59