发表机构
University of Ostrava（俄斯特拉发大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过基准测试EOM-CCSD等方法，首次系统从头算研究Hg₃-Hg₅的吸收光谱，验证EOM-CCSD是描述汞团簇激发态与光学光谱的可靠方法。
AI 中文摘要
我们报道了对小汞团簇（Hg$_{\text{2-5}}$）激发态与吸收光谱的系统从头算研究。对多参考组态相互作用（MR-CISD）和方程-运动耦合簇（EOM-CCSD）方法的基准测试显示，EOM-CCSD/aug-cc-PVTZ-PP重现原子激发能的误差在实验值的±500 cm⁻¹以内，而MR-CISD的偏差约为±1100 cm⁻¹。对于汞二聚体，EOM-CCSD势能曲线给出的吸收带与实验跃迁吻合度极高，渐近激发能与原子参考值匹配紧密。将该方法拓展后，我们首次对Hg₃、Hg₄、Hg₅的吸收光谱开展系统从头算研究，发现它们在37000-60000 cm⁻¹范围内呈现宽吸收带。与实验基准的一致吻合及证实单参考特性的诊断结果，验证了EOM-CCSD是描述汞团簇激发态与光学光谱的可靠方法。
英文摘要
We report a systematic \textit{ab initio} investigation of the excited states and absorption spectra of small mercury clusters (Hg$_{\mathrm{2-5}}$). Benchmarking multi-reference configuration interaction (MR-CISD) and equation-of-motion coupled-cluster (EOM-CCSD) methods shows that EOM-CCSD/aug-cc-PVTZ-PP reproduces atomic excitation energies within $\pm$500 cm$^{-1}$ of experiment, whereas MR-CISD deviates by about $\pm$1100 cm$^{-1}$. For the mercury dimer, EOM-CCSD potential energy curves yield absorption bands in excellent agreement with experimental transitions, while asymptotic excitation energies closely match atomic references. Extending this methodology, we present the first systematic \textit{ab initio} study of absorption spectra of Hg$_{\mathrm{3}}$, Hg$_{\mathrm{4}}$, Hg$_{\mathrm{5}}$, which display broad bands in the ranges of 37000-60000 cm$^{-1}$. The consistent agreement with experimental benchmarks and diagnostics confirming single-reference character validates EOM-CCSD as a robust approach for describing excited states and optical spectra of mercury clusters.
