Two-photon double ionization with finite pulses: Application of the virtual sequential model to helium
Two-photon double ionization with finite pulses: Application of the virtual sequential model to helium
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DOI：
10.1103/physreva.108.013114
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发表时间：
2023-05
影响因子：
2.9
通讯作者：
S. Chattopadhyay;Carlos Marante;B. Schneider;L. Argenti
中科院分区：
文献类型：
--
作者：
S. Chattopadhyay;Carlos Marante;B. Schneider;L. Argenti
作为对双光子双电离过程的从头算描述的一步，我们提出了一个有限脉冲形式的多电子原子虚序模型。该模型依赖于中性和电离靶系统的单电离散射态的从头计算描述。作为原理的证明和基准，该模型被应用到氦原子使用{\ttNewStock}原子光电离代码。角度积分可观测量的结果与现有的TDSE（时间相关薛定谔方程）模拟非常一致，显示了该模型如何能够捕获电子相关性在非顺序机制中的作用，以及自电离状态的影响。在顺序机制中，计算成本相对较低。该模型还再现了超短脉冲的两粒子干涉，这是目前实验技术所能达到的。此外，该模型示出了调制的联合能量分布在附近的自电离状态，这可以用极紫外脉冲的持续时间远长于共振的特征寿命进行探测。这里讨论的形式主义也适用于多电子原子和分子，从而打开了一个窗口，在这些更复杂的系统中的非顺序和顺序双电离。
As a step toward the full \emph{ab-initio} description of two-photon double ionization processes, we present a finite-pulse version of the virtual-sequential model for polyelectronic atoms. The model relies on the \emph{ab initio} description of the single ionization scattering states of both the neutral and ionized target system. As a proof of principle and a benchmark, the model is applied to the helium atom using the {\tt NewStock} atomic photoionization code. The results of angularly integrated observables, which are in excellent agreement with existing TDSE (time-dependent Schr\"odinger equation) simulations, show how the model is able to capture the role of electron correlation in the non-sequential regime, and the influence of autoionizing states in the sequential regime, at a comparatively modest computational cost. The model also reproduces the two-particle interference with ultrashort pulses, which is within reach of current experimental technologies. Furthermore, the model shows the modulation of the joint energy distribution in the vicinity of autoionizing states, which can be probed with extreme-ultraviolet pulses of duration much longer than the characteristic lifetime of the resonance. The formalism discussed here applies also to polyelectronic atoms and molecules, thus opening a window on non-sequential and sequential double ionization in these more complex systems.