Photo double-ionization of CO2 studied by photoelectron-photoelectron coincidence experiments at 20 eV excess energy in equal energy sharing conditions

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D Pub Date : 2024-10-15 DOI:10.1140/epjd/s10053-024-00917-4

Giorgio Turri, Paola Bolognesi, Lorenzo Avaldi

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Abstract

The Triple-Differential Cross Section (TDCS) for the Photo Double-Ionization of carbon dioxide molecule to the CO₂²⁺ X³ Σ_g⁻ ground state has been measured at 20 eV excess energy. In the experiment the coincidence angular distributions of the two photoelectrons, where the direction of one photoelectron has been fixed at 0, 30 and 60° with respect to the direction of the polarization of the incident radiation, have been measured for a condition where the two photoelectrons equally share the excess energy. Care has been taken to perform the measurements with an energy resolution which enabled to isolate the TDCS of the X³Σ⁻_g ground state of the dication. An appreciable contribution to TDCS at a relative angle θ₁₂ = 180° has been observed and attributed to a favorite symmetry of the wavefunction of the two ejected electrons.

Graphical abstract

TDCS of CO₂ measures at photon energy 57.7eV, θ₁=0, 30 and 60° and equal energy sharing of 10 eV are reported as black dots. Panels (a) and (c) report the TDCS as calculated by Alwan et al. (J Phys B: At Mol Opt Phys 48:185203, 2015) using the charge in the Sommerfeld parameters for the oxygen atom of 0.2 (black full curve) and 0.8 (ref full curve). The blue full curve in panels (d)-(f) is the fit to the experiments with the helium=like model by Reddsih and Feaging (J Phys B: At Mol Opt Phys 32:2473, 1999).

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在等能量共享条件下，通过 20 eV 过剩能量下的光电子-光电子重合实验研究二氧化碳的光双电离现象

在 20 eV 的过剩能量下测量了二氧化碳分子光双电离到 CO22+ X3 Σg- 基态的三重差分截面 (TDCS)。在实验中，测量了两个光电子的重合角分布，其中一个光电子的方向相对于入射辐射的偏振方向固定为 0、30 和 60°，测量的条件是两个光电子平均分配过剩能量。测量时注意了能量分辨率，以便能够分离出二阳离子 X3Σ-g 基态的 TDCS。在相对角度 θ12 = 180° 时，观察到对 TDCS 有明显的贡献，这归因于两个射出电子的波函数最喜欢的对称性。图解摘要在光子能量为 57.7eV、θ1=0、30 和 60°，以及 10 eV 等能量共享时测量的二氧化碳 TDCS 以黑点表示。面板 (a) 和 (c) 报告了 Alwan 等人（J Phys B: At Mol Opt Phys 48:185203, 2015）使用氧原子的 Sommerfeld 参数中的电荷 0.2（黑色完整曲线）和 0.8（参考完整曲线）计算的 TDCS。(d)-(f)板中的蓝色全曲线是 Reddsih 和 Feaging（J Phys B: At Mol Opt Phys 32:2473, 1999）用类氦模型拟合的实验结果。

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来源期刊

The European Physical Journal D 物理-物理：原子、分子和化学物理

CiteScore

3.10

自引率

11.10%

发文量

213

审稿时长

3 months

期刊介绍： The European Physical Journal D (EPJ D) presents new and original research results in: Atomic Physics; Molecular Physics and Chemical Physics; Atomic and Molecular Collisions; Clusters and Nanostructures; Plasma Physics; Laser Cooling and Quantum Gas; Nonlinear Dynamics; Optical Physics; Quantum Optics and Quantum Information; Ultraintense and Ultrashort Laser Fields. The range of topics covered in these areas is extensive, from Molecular Interaction and Reactivity to Spectroscopy and Thermodynamics of Clusters, from Atomic Optics to Bose-Einstein Condensation to Femtochemistry.