类氢O、N离子入射Al表面俘获电子布居几率的理论与实验研究  

Theoretical and experimental studies on the captured electron population probability of hydrogen-like O and N ions in collision with Al surface

作　　者：张秉章 宋张勇[2,3] 张明武 刘璇[2,4] 钱程 方兴 邵曹杰[2,3] 王伟 刘俊亮[2,3] 朱志超 孙良亭[2,3] 于得洋 Zhang Bing-Zhang;Song Zhang-Yong;Zhang Ming-Wu;Liu Xuan;Qian Cheng;Fang Xing;Shao Cao-Jie;Wang Wei;Liu Jun-Liang;Zhu Zhi-Chao;Sun Liang-Ting;Yu De-Yang(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Institute of Modern Physics,Chinese Academy of Science,Lanzhou 730000,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]中国科学院近代物理研究所,兰州730000 [3]中国科学院大学核科学与技术学院,北京100049 [4]兰州大学核科学与技术学院,兰州730000

出　　处：《物理学报》2022年第13期115-121,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11675279,12075291)资助的课题。

摘　　要：利用“二态矢量模型”详细研究了高电荷态O^(7+),N^(6+)离子入射Al表面时中间里德伯态的形成过程,给出了电子被俘获至不同量子数(n A=2-7)的几率,以及电子俘获至里德伯态最可能的离子-表面距离.计算结果表明,较大的主量子数nA对应较小的里德伯态几率,因此O^(7+),N^(6+)离子入射Al表面时辐射的X射线主要来源于较小的n A至基态的退激.为了验证计算结果,测量了O^(7+),N^(6+)离子入射Al表面的X射线发射谱,并运用FAC程序计算了不同高里德伯态退激到基态的跃迁能(np–1s).实验测量到O,N的K-X射线峰,其特征峰的中心值接近主量子数n=2至n=1的跃迁能,说明发射的X射线主要来源于2p–1s的跃迁,与“二态矢量模型”理论计算的几率一致.The study of the interaction between highly charged ions and solid surfaces not only has great significance for basic scientific research such as atomic physics,astrophysics,and high energy density physics but also has promising application prospects in biomedicine,nanotechnology,surface analysis,and microelectronics.In this paper,the intermediate Rydberg states formed during highly charged O^(7+) and N^(6+) ions incident on Al surface are studied theoretically by using the two-state vector model.Both the probability of electron capture into different Rydberg states(n A=2-7)and the most probable neutralization distances are given.The calculation shows that the larger principal quantum number n A is relevant to smaller probability.Therefore,the X-rays emitted by O^(7+) and N^(6+) ions incident on the Al surface come mainly from the de-excitation of the smaller n A to the ground state.In order to confirm the calculations,we measured the X-ray emission spectra of O^(7+) and N^(6+) ions in collisions with the Al surface in the energy range of 3–20 keV/q.The experiments were performed at an ECR ion source located in Institute of modern physics.We also calculated the transition energies(np–1 s)from different high Rydberg states to the ground state by using the FAC code.The center of the measured K X-ray peak is close to the calculated transition energy from the principal quantum number n=2 to n=1,it is consistent with our results obtained by the two-state vector model as well.In addition,we found the experimental K X-ray yield for O^(7+) ions incidence at lower energy collisions is almost the same with N^(6+) ions,but larger at higher energy collisions.When the ion incident kinetic energy is low,the X-ray emission is mainly owing to the decay of“above the surface”hollow atoms.Because of the small difference in the critical distances for the capture of electrons by O^(7+) and N^(6+) to form hollow atoms,the X-ray yields produced in both cases are almost the same at low energy collisions.In contrast,as increasing

关 键 词：高电荷态离子 里德伯态 二态矢量模型 X射线 

分 类 号：O56[理学—原子与分子物理]