【摘 要】
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Coherent vibrational dynamics can be observed in atomically precise gold nanoclusters using femtosec-ond time-resolved pump-probe spectroscopy.It can not only reveal the coupling between electrons and vibrations,but also reflect the mechanical and elec-tr
【机 构】
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Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technolo
论文部分内容阅读
Coherent vibrational dynamics can be observed in atomically precise gold nanoclusters using femtosec-ond time-resolved pump-probe spectroscopy.It can not only reveal the coupling between electrons and vibrations,but also reflect the mechanical and elec-tronic properties of metal nanoclusters,which holds potential applications in biological sensing and mass detection.Here,we investigated the coherent vibra-tional dynamics of[Au25(SR)18]-nanoclusters by ul-trafast spectroscopy and revealed the origins of these coherent vibrations by analyzing their frequency,phase and probe wavelength distributions.Strong coherent oscillations with frequency of 40 cm-1 and 80 cm-1 can be reproduced in the excited state dynamics of[Au25(SR)18]-,which should originate from acoustic vibra-tions of the Au13 metal core.Phase analysis on the oscillations indicates that the 80 cm-1 mode should arise from the frequency modulation of the electronic states while the 40 cm-1 mode should originate from the amplitude modulation of the dynamic spectrum.Moreover,it is found that the vibration frequencies of[Au25(SR)18]-obtained in pump-probe mea-surements are independent of the surface ligands so that they are intrinsic properties of the metal core.These results are of great value to understand the electron-vibration coupling of metal nanoclusters.
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