AI 中文总结
本研究通过多种光谱与模拟方法，揭示原子级精确金纳米团簇中光激发下金-配体界面的动态振动耦合机制，确立其为激发态能量流与光化学功能的微观关联。
AI 中文摘要
原子级精确金纳米团簇因电子结构源于强金属-配体相互作用，在光催化和能量转换领域具有广泛应用前景。然而，这些相互作用大多被静态讨论，光激发下金-配体界面的动态重组机制尚不明确。本研究采用超快瞬态光栅光谱、二维电子光谱、从头算及层级运动方程模拟，对棒状[Au25(PPh3)10(SC2H5)5Cl2]2+开展研究。多维光谱解析出多条电子弛豫路径及相干结构运动层级，从局域金-配体畸变到整体框架振动；小波分析显示，激发后即刻出现高频金-配体振动，低频集体模式则通过态间振动耦合后续出现，表明结构相干性呈序贯式再分布。模拟复现了非线性响应并明确了负责的微观振动耦合。结果表明，光激发驱动金-配体键网络发生连续超快重组，热化前瞬时改变界面电子结构。本研究确立了动态金-配体界面作为原子级精确纳米团簇中激发态能量流与光化学功能间的微观关联。
英文摘要
Atomically precise gold nanoclusters are versatile for photocatalysis and energy conversion because their electronic structure stems from strong metal-ligand interactions. However, these interactions are mostly discussed statically, leaving dynamic reorganization of Au-ligand interfaces under photoexcitation unclear. We investigate rod-shaped [Au25(PPh3)10(SC2H5)5Cl2]2+ using ultrafast transient-grating spectroscopy, two-dimensional electronic spectroscopy, ab initio calculations, and hierarchical equations-of-motion simulations. The multidimensional spectra resolve multiple electronic relaxation pathways and a hierarchy of coherent structural motions, from localized Au-ligand distortions to collective framework vibrations. Wavelet analysis reveals that high-frequency Au-ligand vibrations emerge immediately after excitation, whereas low-frequency collective modes appear later through interstate vibronic coupling, indicating sequential redistribution of structural coherence. Simulations reproduce the nonlinear response and identify the microscopic vibronic couplings responsible. The results show that photoexcitation drives continuous ultrafast reorganization of the Au-ligand bonding network, transiently reshaping interfacial electronic structure before thermalization. This work establishes dynamic Au-ligand interfaces as the microscopic link between excited-state energy flow and photochemical function in atomically precise nanoclusters.
Comments30 pages, 5 figures
