C_(4)^(-)离子的低能电子弹性散射研究:共振态与同分异构  

Low-energy electron elastic scattering of C_(4)^(-) anions:Resonance states and conformers

作　　者：李炅远 孟举 王克栋[1] Li Jiong-Yuan;Meng Ju;Wang Ke-Dong(School of Physics,Henan Normal University,Xinxiang 453007,China)

机构地区：[1]河南师范大学物理学院,新乡453007

出　　处：《物理学报》2024年第24期91-98,共8页Acta Physica Sinica

基　　金：河南省优秀青年科学基金(批准号:212300410054)资助的课题.

摘　　要：基于从头算R-矩阵方法,在固定核近似下,采用单态密耦合(close couple,CC)模型,研究了低能电子与C_(4)^(-)负离子的散射过程.研究结果预测了该负离子四种异构体在0-12 eV的能区内的电子弹性散射积分截面,研究了存在的共振态以及构型变化对共振态位置与宽度的影响.此外还对理论结果与现有实验数据进行了细致的比较和分析,结果表明,实验观测到的8.8 eV共振峰主要是异构体A的∑_(u)^(+)和∑_(u)^(-)共振态的贡献以及少部分来自异构体C的A2共振态的贡献.散射截面上揭示了异构体A存在五个共振态,异构体B有三个共振态,异构体C和D各存在四个共振态.最后,根据玻尔兹曼分布计算了不同温度下各异构体的布居,模拟了在常温条件下C_(4)^(-)的低能电子弹性散射积分截面,与已有的实验结果符合较好.同时还发现在3.3 eV的低能区处存在一个宽度为0.20 eV的势形共振态,为实验的进一步证实提供了理论参考.This paper reports low-energy electron scattering with C_(4)^(-) anions by using the ab initio R-matrix method in the single state close-coupling (CC) model and the fixed-nuclei approximation. We predict the elastic integral scattering cross sections (ICSs) of four conformers of C_(4)^(-) ions in an energy range of 0 < E ≤12 eV and discuss the effects of configuration changes on resonance position and width. Additionally, the theoretical results and experimental data are compared and analyzed. The results indicate that the 8.8 eV resonance peak observed in experiment is mainly derived from the ∑_(u)^(+) and ∑_(u)^(-) resonances of the conformer A and the A2 resonance of the conformer C. The scattering cross-section reveals that the conformer A has five resonant states, and the conformer B has three resonances, while C and D each have four resonances. Finally, we use the Boltzmann distribution to calculate the populations of different conformers at different temperatures, and simulate the low-energy electron elastic integrated scattering cross-section at room temperature, which is in good agree-ment with available experimental results. We also find a shape resonance with a width of 0.20 eV at 3.3 eV in our total cross sections, which is not detected in the existing experimental results. This provides new opportunities for measurement.

关 键 词：电子散射 C_(4)^(-)离子构象 R-矩阵方法 共振态 散射截面 

分 类 号：O4[理学—物理]