Ultrafast Rydberg-state dissociation in oxygen: Identifying the role of multielectron excitations
Ultrafast Rydberg-state dissociation in oxygen: Identifying the role of multielectron excitations
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DOI：
10.1103/physreva.99.063403
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发表时间：
2019-06
影响因子：
2.9
通讯作者：
A. Plunkett;N. Harkema;R. Lucchese;C. W. McCurdy;A. Sandhu
中科院分区：
文献类型：
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作者：
A. Plunkett;N. Harkema;R. Lucchese;C. W. McCurdy;A. Sandhu
作者(S)：Plunkett，A；Harkema，N；Lucchese，RR；McCurdy，CW；Sandhu，A|摘要：©2019美国物理学会。我们用飞秒瞬时光电子能谱研究了分子氧高激发态的碎裂动力学。极紫外光脉冲填充自电离里德堡序列，聚集到O2+cςu-4，而飞秒近红外(IR)脉冲被用来在这些态解离时进行光致电离。通过监测微分光电子能谱随时间延迟的变化，我们可以得到这些里德堡态的驰豫寿命。我们观察到与4P激发原子氧碎片的形成相对应的光电子信号，这并不是(O2+cςu-4)NLσg里德堡系列的预期解离产物。对含时光电子能谱的分析和光电离计算表明，这一碎片是由以前未被探索的(O2+Πg4)4P排斥态产生的，与预期相反，这种多电子激发途径呈现出相当大的截面。我们的研究表明，双色时间分辨差示光电子能谱是研究这种多电子激发态碎裂动力学的一种很好的工具，这是其他方法不容易探测到的。
Author(s): Plunkett, A; Harkema, N; Lucchese, RR; McCurdy, CW; Sandhu, A | Abstract: © 2019 American Physical Society. We investigated the fragmentation dynamics of highly excited states of molecular oxygen using femtosecond transient photoelectron spectroscopy. An extreme ultraviolet (XUV) pulse populates the autoionizing Rydberg series converging to O2+cςu-4, and a femtosecond near-infrared (IR) pulse was used to photoionize these states as they dissociate. Monitoring the differential photoelectron spectra as a function of time delay allowed us to obtain the relaxation lifetimes of these Rydberg states. We observed a photoelectron signal corresponding to the formation of a 4p excited atomic oxygen fragment, which is not an expected dissociation product of the (O2+cςu-4)nlσg Rydberg series. Analysis of the time-dependent photoelectron spectra and photoionization calculations indicate that this fragment results from a previously unexplored (O2+Πg4)4p repulsive state and that, contrary to expectations, this multielectron excitation pathway presents a substantial cross section. Our study demonstrates that two-color time-resolved differential photoelectron spectroscopy is an excellent tool to study the fragmentation dynamics of such multielectron excited states, which are not easily probed by other means.