In a previous work Sims and Hagstrom [J. Chem. Phys. 140, 224312 (2014)] reported Hylleraas-Configuration Interaction (Hy-CI) method variational calculations for the neutral atom and positive ion 1S ground states of the beryllium isoelectronic sequence. The Li- ion, nominally the first member of this series, has a decidedly different electronic structure. This paper reports the results of a large, comparable calculation for the Li- ground state to explore how well the Hy-CI method can represent the more diffuse L shell of Li- which is representative of the Be(2sns) excited states as well. The best non-relativistic energy obtained was -7.500 776 596 hartree, indicating that 10 - 20 nh accuracy is attainable in Hy-CI and that convergence of the r12r34 double cusp is fast and that this correlation type can be accurately represented within the Hy-CI model.

中文翻译：

---

负锂离子1S基态的Hylleraas-Configuration相互作用研究。

在先前的著作《 Sims and Hagstrom [J. 化学 物理 140，224312（2014）]报道了铍等电子序列的中性原子和正离子1S基态的Hylleraas-Configuration Interaction（Hy-CI）方法变异计算。锂离子，名义上是该系列的第一成员，具有截然不同的电子结构。本文报告了对Li基态的大量可比计算的结果，以探索Hy-CI方法如何更好地表现Li-的更弥散的L壳层，L壳层也代表了Be（2sns）激发态。获得的最佳非相对论能量是-7.500 776 596 hartree，