The ab initio $R$-matrix with time method has recently been extended to allow simulation of fully nonperturbative multielectron processes in molecules driven by ultrashort arbitrarily polarized strong laser fields. Here we demonstrate the accuracy and capabilities of the current implementation of the method for two targets: We study single-photon and multiphoton ionization of ${\mathrm{H}}_2$ and one-photon and strong-field ionization of ${\mathrm{H}}_2\mathrm{O}$ and compare the results to available experimental and theoretical data as well as our own time-independent $R$-matrix calculations. We obtain a highly accurate description of total and state-to-state single-photon ionization of ${\mathrm{H}}_2\mathrm{O}$ and, using a simplified coupled-channel model, we show that state coupling is essential to obtain qualitatively correct results and that its importance as a function of laser intensity changes. We find that electron correlation plays a more important role at low intensities (up to approximately 50 $\text{TW}/{\mathrm{cm}}^2$).

中文翻译：

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使用分子R-矩阵随时间方法对H2和H2O进行微扰和非微扰光电离

该从头 $\mathrm{[R}$随时间变化的矩阵方法最近得到扩展，可以模拟由超短任意极化强激光场驱动的分子中的完全非扰动多电子过程。在这里，我们演示了针对两个目标的当前方法实现的准确性和功能：我们研究了单光子和多光子电离${\mathrm{H}}_2$ 以及单光子和强场电离 ${\mathrm{H}}_2\mathrm{Ø}$ 并将结果与​​可用的实验和理论数据以及我们自己的时间无关的结果进行比较 $\mathrm{[R}$-矩阵计算。我们获得了总的和状态间单光子电离的高度准确的描述。${\mathrm{H}}_2\mathrm{Ø}$并且使用简化的耦合通道模型，我们表明状态耦合对于获得定性正确的结果至关重要，并且其重要性随激光强度的变化而变化。我们发现，在低强度（高达约50）下，电子相关性起着更重要的作用。$\text{TW}/{\mathrm{厘米}}^2$）。