原子团簇中低位电子四极态的双光子激发
Two-Photon Excitation of Low-Lying Electronic Quadrupole States in Atomic Clusters
摘要：
本文提出了一种简单的测量自由小变形金属团簇中电子四极模的布居和探测方案。该计划进行了分析的TDLDA（含时局域密度近似）计算。作为测试用例，考虑变形的簇$Na^+_{11}$。长寿命的四极子振荡是通过共振双光子（双偶极）激发产生的，然后通过探测脉冲产生的光电子谱中卫星的出现来检测。飞秒泵浦和探测脉冲的强度$I = 2\cdot 10^{10} - 2\cdot 10^{11} W/cm^2$和脉冲持续时间$T = 200 - 500$ fs被认为是最佳的。感兴趣的模式是由一个单一的电子空穴对，所以他们的能量，结合空穴态的光电子数据，允许收集新的信息平均场谱的价电子在HOMO-LUMO区域。此外，该方案允许估计电子空穴对的寿命，从而电子能量到离子热的弛豫时间。
英文摘要：
A simple scheme of population and detection of low-lying electronic quadrupole modes in free small deformed metal clusters is proposed. The scheme is analyzed in terms of the TDLDA (time-dependent local density approximation) calculations. As test case, the deformed cluster $Na^+_{11}$ is considered. Long-living quadrupole oscillations are generated via resonant two-photon (two-dipole) excitation and then detected through the appearance of satellites in the photoelectron spectra generated by a probe pulse. Femtosecond pump and probe pulses with intensities $I = 2\cdot 10^{10} - 2\cdot 10^{11} W/cm^2$ and pulse duration $T = 200 - 500$ fs are found to be optimal. The modes of interest are dominated by a single electron-hole pair and so their energies, being combined with the photoelectron data for hole states, allow to gather new information about mean-field spectra of valence electrons in the HOMO-LUMO region. Besides, the scheme allows to estimate the lifetime of electron-hole pairs and hence the relaxation time of electronic energy into ionic heat.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
