碱金属与碱土金属原子构成的双原子分子阴离子
Diatomic molecular anions of alkali-metal and alkaline-earth-metal atoms
浏览论文内容
中文总结 AI 辅助
本研究通过多种高精度计算方法系统研究了碱金属与碱土金属构成的双原子分子阴离子的基态与激发态性质，预测了中性基态与阴离子激发态的交叉，为超冷混合体系实验提供理论参考。
中文摘要 AI 辅助
由于阴离子的电子具有弥散且弱束缚的特性，对阴离子的研究本质上比对中性粒子和阳离子的研究更具挑战性。本文对由碱金属（Li、Na、K、Rb、Cs、Fr）和碱土金属（Be、Mg、Ca、Sr、Ba、Ra）原子构成的基态双原子分子阴离子开展了全面的计算研究。我们研究了21种处于X$^{2}Σ^{+}$电子态的碱金属双原子阴离子，以及36种处于X$^{1}Σ^{+}$电子态的碱金属-碱土金属双原子阴离子。计算采用了一系列耦合簇方法，结合大高斯基组，并针对较重元素使用了小核相对论能量一致赝势。我们计算了势能曲线、固有电偶极矩和静态极化率，并评估了结果的收敛性与不确定性。此外，我们还利用多参考组态相互作用方法和运动方程电子附着耦合簇方法，研究了碱金属分子阴离子的激发电子态，包括价束缚态和偶极束缚态。我们预测了基态中性态与激发阴离子态之间的交叉，这种交叉可能会增强共振电子附着及后续的阴离子解离过程。这一发现可能与超冷基态碱金属分子和里德伯原子混合体系的实验相关。
英文摘要
Studies of anions are inherently more challenging than investigations of neutrals and cations because of the diffuse and weakly bound character of an anionic electron. Here, we present a comprehensive computational examination of ground-state diatomic molecular anions composed of alkali-metal (Li, Na, K, Rb, Cs, Fr) and alkaline-earth-metal (Be, Mg, Ca, Sr, Ba, Ra) atoms. We study 21 alkali-metal diatomic anions in the X$^{2}Σ^{+}$ electronic state and 36 alkali-metal--alkaline-earth-metal diatomic anions in the X$^{1}Σ^{+}$ electronic state. The calculations employ a hierarchy of the coupled cluster methods, combined with large Gaussian basis sets and small-core relativistic energy-consistent pseudopotentials for heavier elements. We compute potential energy curves, permanent electric dipole moments, and static polarizabilities, and we assess convergence and uncertainties of our results. Additionally, using the multireference configuration interaction and equation-of-motion electron-attachment coupled cluster methods, we investigate excited electronic states of alkali-metal molecular anions, including valence-bound and dipole-bound states. We predict crossings between ground neutral and excited anionic states, which may enhance resonant electron attachment and subsequent anion dissociation. This finding may be relevant for experiments with mixtures of ultracold ground-state alkali-metal molecules and Rydberg atoms.
