Studies have shown significant discrepancies between the recent experiment [Berg et al., Phys. Rev. Lett. 120, 055002 (2018)] and current theoretical calculations on the electron-impact ionization cross section of ions in warm dense magnesium. Here, we present a systematic study the effects of the ionic correlations and free-electron screening on the electron-impact ionization of ions in warm dense matter. The ionic correlation and the free-electron screening effects yield additional Hermitian terms to the calculation of the ionic central-force-field potential, which significantly change the electronic structure compared with that of the isolated ion. In calculating the electron-impact ionization, we describe the impact and ionized electrons using a damped-distorted wave function, which considers the momentum relaxation of free electrons due to collisions with other free electrons and ions. We reproduce the electron-impact ionization process for ${\mathrm{Mg}}^{7+}$ in the solid-density plasma and increase the ionization cross section by one order of magnitude compared with that of the isolated ion, which excellently agrees with the experimental result of Berg et al.

中文翻译：

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由温暖的密集环境引起的电子撞击电离的增强

研究表明，最近的实验之间存在显着差异 [Berg et al. ，物理。牧师莱特。 120, 055002 (2018)] 和当前关于暖致密镁离子的电子碰撞电离截面的理论计算。在这里，我们系统地研究了离子相关性和自由电子屏蔽对温暖致密物质中离子的电子碰撞电离的影响。离子相关性和自由电子屏蔽效应为离子中心力场势的计算产生了额外的厄米项，与孤立离子相比，这显着改变了电子结构。在计算电子撞击电离时，我们使用阻尼失真波函数来描述撞击和电离电子，该函数考虑了由于与其他自由电子和离子碰撞而导致的自由电子的动量弛豫。我们重现了电子撞击电离过程${镁}^{7+}$在固体密度等离子体中，与孤立离子相比，电离截面增加了一个数量级，这与 Berg等人的实验结果非常吻合。