In order to investigate the electronic correlation effects in the ionization potentials of small lithium clusters, we obtain accurate ground-state energies using the diffusion quantum Monte Carlo simulation. We decompose both the adiabatic and vertical ionization potentials of the clusters into physical components to analyze the nature of the superalkali characteristics of the lithium clusters. We find that the electron-correlation contribution to the ionization potential is mostly canceled out by the orbital relaxation with net contribution less than 0.5 eV. The superalkali characteristics of the clusters is basically determined by the electrostatic and exchange interactions.

中文翻译：

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基于量子蒙特卡洛模拟的小型超碱性锂簇的电离势分析

为了研究小锂簇的电离势中的电子相关效应，我们使用扩散量子蒙特卡罗模拟获得了准确的基态能量。我们将团簇的绝热和垂直电离势分解为物理成分，以分析锂团簇的超碱性特征的性质。我们发现，电子相关性对电离势的贡献大部分被轨道弛豫抵消，其净贡献小于0.5 eV。团簇的超碱性特征基本上由静电和交换相互作用决定。