The screening effect of dense quantum plasmas on the ground and singly excited states of two-electron atoms are investigated by employing the explicitly correlated Hylleraas configuration-interaction wave functions in the framework of Ritz variational principle. Exponential cosine screened Coulomb potential is used to model the electron–nucleus​ and interelectronic interactions in the atomic systems. Energy levels for the ground and $1\mathrm{s}n\mathrm{l}$ ${}^{1,3}\mathrm{L}$ (n$\le 5$ and $\mathrm{l}\le 4$) singly excited states of H${}^{-}$, He, Li${}^{+}$, Be${}^{2+}$, and B${}^{3+}$ are reported for screening parameters varying from zero to the value nearing corresponding critical screening parameter. Convergence of our calculations are estimated by systematically increasing the number of basis functions. A thorough comparison with available theoretical predictions on the ground state energies at various screening parameters is made, while for the excited states a comparison with the well-established energies of unscreened atoms is performed. The variation of ionization energy and the validity of Hund’s rule for two-electron systems in dense quantum plasmas are analyzed.

在 Ritz 变分原理的框架内，通过使用显式相关的 Hylleraas 构型相互作用波函数，研究了稠密量子等离子体对双电子原子的基态和单激发态的屏蔽效应。指数余弦筛选库仑势用于模拟原子系统中的电子-核和电子间相互作用。地面能量水平和$1\mathrm{秒}n\mathrm{升}$ ${}^{1,3}\mathrm{升}$( n$\le 5$ 和 $\mathrm{升}\le 4$) H 的单激发态${}^{-}$, 何, 李${}^{+}$， 是${}^{2+}$, 和 B${}^{3+}$报告了从零到接近相应临界筛选参数的值的筛选参数。我们计算的收敛性是通过系统地增加基函数的数量来估计的。对各种筛选参数下基态能量的可用理论预测进行了彻底比较，而对于激发态，则与未筛选原子的公认能量进行了比较。分析了稠密量子等离子体中双电子系统电离能的变化和洪德法则的有效性。