Chemical Physics and NanoLund, Lund University, Box 124, 22100 Lund, Sweden.
Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
Nat Commun. 2017 May 26;8:15577. doi: 10.1038/ncomms15577.
DNA-templated silver nanoclusters of a few tens of atoms or less have come into prominence over the last several years due to very strong absorption and efficient emission. Applications in microscopy and sensing have already been realized, however little is known about the excited-state structure and dynamics in these clusters. Here we report on a multidimensional spectroscopy investigation of the energy-level structure and the early-time relaxation cascade, which eventually results in the population of an emitting state. We find that the ultrafast intramolecular relaxation is strongly coupled to a specific vibrational mode, resulting in the concerted transfer of population and coherence between excited states on a sub-100 fs timescale.
在过去的几年中，由于具有很强的吸收和高效的发射，少数几十个原子或更少的 DNA 模板银纳米团簇引起了人们的关注。这些纳米团簇已经在显微镜和传感等领域得到了应用，然而，人们对这些纳米团簇的激发态结构和动力学知之甚少。在这里，我们报告了对能级结构和早期弛豫级联的多维光谱研究，最终导致了发射态的粒子数增加。我们发现，超快的分子内弛豫与一个特定的振动模式强烈耦合，导致在 100fs 以内的时间尺度上，激发态之间的粒子数和相干性的协同转移。
