Plasmon-driven sub-picosecond breathing of metal nanoparticles
Plasmon-driven sub-picosecond breathing of metal nanoparticles
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DOI：
10.1039/c7nr04536k
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发表时间：
2017-09-14
期刊：
影响因子：
6.7
通讯作者：
Sanchez, Cristian G.
中科院分区：
文献类型：
--
作者：
Bonafe, Franco P.;Aradi, Balint;Sanchez, Cristian G.
利用含时密度泛函理论（TDDFT）分子动力学方法，首次对强激光脉冲作用下二十面体银纳米粒子的量子动力学进行了实时原子模拟。我们确定的出现亚皮秒呼吸样的径向振荡后立即开始激光脉冲激发，随着场强的增加，幅度增加。纳米粒子对激光激发的超快动态响应指向一种新的机制，而不是之前假设的平衡电子-声子散射，这需要更长的时间尺度。在激光激发过程中观察到的所有键的急剧减弱，由于等离子体激元阻尼成激发电子在反键状态。这种键的突然减弱导致纳米颗粒的均匀膨胀，并启动相干呼吸振荡。
We present the first real-time atomistic simulation on the quantum dynamics of icosahedral silver nanoparticles under strong laser pulses, using time dependent density functional theory (TDDFT) molecular dynamics. We identify the emergence of sub-picosecond breathing-like radial oscillations starting immediately after laser pulse excitation, with increasing amplitude as the field intensity increases. The ultrafast dynamic response of nanoparticles to laser excitation points to a new mechanism other than equilibrium electron-phonon scattering previously assumed, which takes a much longer timescale. A sharp weakening of all bonds during laser excitation is observed, thanks to plasmon damping into excited electrons in anti-bonding states. This sudden weakening of bonds leads to a uniform expansion of the nanoparticles and launches coherent breathing oscillations.