Coherent vibrational dynamics of Au144(SR)60 nanoclusters

Wei Zhang; Jie Kong; Yingwei Li; Zhuoran Kuang; He Wang; Meng Zhou

doi:10.1039/d2sc02246j

Coherent vibrational dynamics of Au₁₄₄(SR)₆₀ nanoclusters

Chem Sci. 2022 Jun 17;13(27):8124-8130. doi: 10.1039/d2sc02246j. eCollection 2022 Jul 13.

Authors

Wei Zhang¹, Jie Kong¹, Yingwei Li², Zhuoran Kuang³, He Wang⁴, Meng Zhou^{1

4}

Affiliations

¹ Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China Hefei Anhui 230026 China mzhou88@ustc.edu.cn.
² Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street Cambridge Massachusetts 02138 USA.
³ School of Science, Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 P. R. China.
⁴ Department of Physics, University of Miami Coral Gables Florida 33146 USA.

Abstract

The coherent vibrational dynamics of gold nanoclusters (NCs) provides important information on the coupling between vibrations and electrons as well as their mechanical properties, which is critical for understanding the evolution from a metallic state to a molecular state with diminishing size. Coherent vibrations have been widely explored in small-sized atomically precise gold NCs, while it remains a challenge to observe them in large-sized gold NCs. In this work, we report the coherent vibrational dynamics of atomically precise Au₁₄₄(SR)₆₀ NCs via temperature-dependent femtosecond transient absorption (TA) spectroscopy. The population dynamics of Au₁₄₄(SR)₆₀ consists of three relaxation processes: internal conversion, core-shell charge transfer and relaxation to the ground state. After removing the population dynamics from the TA kinetics, fast Fourier transform analysis on the residual oscillation reveals distinct vibrational modes at 1.5 THz (50 cm^-1) and 2 THz (67 cm^-1), which arise from the wavepacket motions along the ground-state and excited-state potential energy surfaces (PES), respectively. These results are helpful for understanding the physical properties of gold nanostructures with a threshold size that lies in between those of molecular-like NCs and metallic-state nanoparticles.