Crossover in the photoionization processes of neon clusters with increasing EUV free-electron-laser intensity
Crossover in the photoionization processes of neon clusters with increasing EUV free-electron-laser intensity
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随着 EUV 自由电子激光强度的增加，氖簇光电离过程的交叉
DOI：
10.1103/physreva.88.043203
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发表时间：
2013-10
影响因子：
2.9
通讯作者：
Ri Ma, et al
中科院分区：
文献类型：
--
作者：
S. Yase;K. Nagaya;Y. Mizoguchi;M. Yao;H. Fukuzawa,;K. Motomura;A. Yamada;Ri Ma, et al
测量了相对较大(约5000个原子)的霓虹团簇在20.3 eV极紫外光脉冲照射下的电子发射光谱和总电子产额，与相变相对应。目前的电子发射谱与经历顺序电离的Ar团簇的电子发射谱显著不同[Bostedt，Phys.莱特牧师。100,133401(2008)PRLTAO0031-900710.1103/PhysRevLett.100.133401]，可以解释为在低自由电子激光强度下占主导地位的低能指数尾巴和随时间增长的中等能量高斯型峰值的叠加。相应地，总的电子产额表现出有趣的依赖性。特别是，在中介领域出现了一个平台期。这些结果表明，从热电子到双光子光电子发射的电离机制发生了交叉。对于纳米等离子体的形成，提出了激子-莫特相变。
Electron emission spectra and total electron yields were measured for relatively large (about 5000 atoms) neon clusters that were irradiated by extreme ultraviolet pulses with 20.3 eV, corresponding to thetransition. The present electron emission spectra are remarkably different from those for Ar clusters undergoing sequential ionization [Bostedt , Phys. Rev. Lett. 100, 133401 (2008)PRLTAO0031-900710.1103/PhysRevLett.100.133401] and can be interpreted as a superposition of a low-energy exponential tail, dominant at a low free-electron-laser intensity, and an intermediate-energy Gaussian-like peak which grows with. Correspondingly, the total electron yield exhibits interestingdependence. Especially, a plateau appears in the intermediaterange. These results suggest a crossover in the ionization mechanism from thermal electron to two-photon photoelectron emission. An exciton-Mott transition is proposed for the formation of nanoplasma.