Production of recoil ions He^i＋ accompanied by single electron loss of 0.2-7 MeV C^q＋ and 0.25-5 MeV O^q＋ （q = 1- 4） ions

Target ionization accompanied with projectile electron loss is investigated for 0.2-7 MeV C^q＋ （q = 1 - 4） with He and 0.25-5 MeV O^q＋ （q = 1 - 4） with He collisions. For projectile single-electron loss channel, the He double-to-single ionization ratio R is nearly independent of projectile charge state but dependent on the nuclear charge of projectile Zp. The results are analysed with atomic structure qualitatively. So far there have not existed the experimental data comparable with our results, to our knowledge. The ratio R is interpreted in terms of the two-step mechanism. This analysis agrees well with similar experiments in the literature.     

Multiple ionization of argon accompanied by electron loss and capture of 0.22-6.35 MeV C^q＋ ions

In this paper a projectile ions recoil ions coincidence technique is employed to investigate the target ionization and projectile charge state changing processes in the collision of 0.22-6.35 MeV Cq^＋ （q = 1 - 4） ions with argon atoms. The partial cross section ratios of the double, triple, quadruplicate ionization to the single ionization （or the single capture） of argon associated with single electron loss （or single electron capture） by the projectile are measured and compared with the previous experimental results. In the present experiment, it is observed that the ratios of ionization cross sections R associated with single loss and single capture depend strongly on the projectile charge state and vary significantly with different reaction channels as impact energy increases. In addition, this paper gets empirical scaling laws for the ionization cross section ratios R corresponding to the projectile single loss and finds that the ratios of the double ionization to the single ionization associated with single electron capture remain constant in the present energy range.     

Single electron loss in and atomic the collisions of C^3＋ hydrogen

This paper studies the projectile electron loss cross sections of C^3＋ colliding with atomic hydrogen in the frame work of extended over-barrier model at intermediate velocities （25 keV/u-600 keV/u）. The electron loss is calculated in terms of the interaction between the screened target nucleus and the active projectile electron and of the interaction between projectile electron and target electron. Compared with the convergent close-coupling calculations, screening and anti-screening calculations, this model satisfactorily reproduces the experimentally obtained energy dependence of the electron-impact ionisation cross sections and the single electron loss cross sections over the energy range investigated here.     

Experimental study of cross-section ratios in the collisions of Cq＋ and oq＋（q= 1-4） on atomic helium in strong-interaction region

We have measured the cross-section ratios of helium induced by C^q+ and O^q+ (q=1-4) in an energy range from 20 keV/amu to 500 keV/amu, and obtained the two-dimensional spectra by employing the coincidence method combined with the MPA-3 data acquisition system. Hence, we obtain the ratios of total single-ionization cross-sections (SI, SC, SLSI, and DLSI), total double-ionization cross-sections (DI, DC, TI, SLDI, and DLDI) and cross-sections of every process (SI, SC, SLSI, DLSI, DI, DC, TI, SLDI, and DLDI), which induce the single-ionization and double-ionization, to the total cross sections respectively. The competitive relations between the reaction-channels and the experimental data law of each reaction-channel are revealed explicitly, and the qualitative explanations involved in those results are also presented accordingly.     

Angular Differential Cross-Section for Ionization of Helium in C^6＋ Ion Collision

With the help of the density operator, the angular differential cross-section for ionization of helium is calculated within the framework of the one-centre atomic-orbital close-coupling method. We consider a naked C^6 ion as projectile with an energy of 2.5 MeV/a.u. Our result agrees well with the experimental data and the other theoretical calculations such as the first Born approximation, various Distorted Wave models and the classical trajectory Monte Carlo simulation.     

54Xe^q＋（q=1,2）与H和He碰撞的电荷剥离截面

采用二体碰撞近似和托马斯－费米近似方法计算了多电荷离子５４Ｘｅｑ＋ （ｑ ＝ １,２ ）与中性原子Ｈ和Ｈｅ 碰撞的电荷剥离截面、电子动量分布和离子势函数分布。计算结果与平面波玻恩近似结果符合得较好     

Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar^16＋ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization （SI） to single capture （SC） is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u..     

Cross sections of Oq+（q=1-4） electron loss in collisions with He,Ne and Ar

Electron-loss cross sections of O q+(q = 1 4) colliding with He,Ne and Ar atoms are measured in the intermediate velocity regime.The ratios of the cross sections of two-electron loss to that of one-electron loss R 21 are presented.It is shown that single-channel analysis is not sufficient to explain the results,but that projectile electron loss,electron capture by the projectile and target ionization must be considered together to interpret the experimental data.The screening and antiscreening effects can account for the threshold velocity results,but cannot explain the dependence of the ratio R 21 on velocity quantitatively.In general,the effective charge of the target atom increases with velocity increasing because the high-speed projectile ion can penetrate into the inner electronic shell of target atom.Ne and Ar atoms have similar effective charges in this velocity regime,but He atoms have smaller ones at the same velocities due to its smaller nuclear charge.     

低能He2+-He反应中单电子俘获微分散射过程的实验研究

利用冷靶反冲离子动量谱仪装置系统研究了20—40 keV He²⁺-He碰撞体系的态选择单电子俘获过程,实验获得了单电子俘获过程的态选择截面以及角微分截面.在所研究的能区范围,电子俘获到L壳层的截面最大,为主要的反应道,这与分子库仑过垒模型的反应窗理论的预测一致.实验测量的态选择截面与原子轨道紧耦合的计算结果很好地符合,与光谱方法的测量结果存在一定的差别,主要原因是光谱方法不能测量完整的反应通道信息.实验结果表明,总角微分截面在小角度范围主要来源于电子俘获到基态的贡献,在大角度范围主要来自电子俘获到激发态的贡献;电子俘获到基态的和激发态的角微分截面均出现振荡结构,这种振荡来源于电子俘获反应中分子轨道之间的相干效应.实验测量的角微分截面与其他实验和紧耦合方法的计算结果进行了比较和分析. 关键词： 冷靶反冲离子动量谱仪 态选择电子俘获 态选择截面 角微分截面     

不同能量的氦原子与同位素分子H2(D2，T2)碰撞分波截面的理论计算

用Tang-Toennies势模型和密耦近似方法计算了不同能量下惰性气体原子He与H₂及其同位素D₂,T₂替代碰撞体系的振转激发碰撞截面. 通过分析He-H₂(D₂,T₂)各碰撞体系分波截面的差异,总结出在H₂分子的对称同位素替代情形下He-H₂(D₂,T₂)碰撞体系分波截面随量子数和体系 关键词： 散射截面 密耦方法 同位素     

Theoretical calculation of the partial cross section for first vibrational excitation in He-H2（D2,T2） collisions

In this paper, close-coupling method was applied to the He-H2 （D2,T2） system, and the first vibrational excitation cross sections of ＇00-10, 00-12, 00-14, 00-16＇ at different incident energy have been calculated. By analyzing the ditferences of these partial wave cross sections, this paper have obtained the change rules of the partial wave cross sections with increases of quantum number, and with change of reduced mass of system. Based on the calculation, influence on the partial wave cross sections brought by the variations in the reduced mass of systems and in the relative kinetic energy of incident atoms is discussed.[第一段]     

用紧耦合方法研究C4+和O6+与He原子碰撞

用双中心原子轨道紧耦合方法计算了C4+-He以及O6+-He碰撞的单俘获总截面,入射离子的能量范围为10～100keV/amu,所得计算结果在实验误差范围内与实验值很好符合.对满壳层入射离子,研究了单俘获截面随入射离子电荷态的变化,并讨论了原子轨道展开波函数数目对计算结果的影响.p     

3He(4He)与H2分子碰撞的同位素效应研究

用公认精确度较高的密耦近似方法计算了入射能量E=05eV时惰性气体原子³He(⁴He)与H₂分子替代碰撞体系的转动激发碰撞截面.通过分析³He(⁴He)-H₂碰撞体系分波截面和微分截面的差异,总结出在氦原子的同位素替代情形下³He(⁴He)-H₂碰撞体系分波截面和微分截面随分波数增加和同位素原子质量改变的变化规律. 关键词： 散射截面 密耦方法 同位素替代 散射角     

紧耦合方法研究离子原子碰撞的单俘获过程

介绍了双中心原子轨道紧耦合方法计算离子原子碰撞的单俘获截面的基本原理，对于双中心 原子轨道紧耦合方法，找到一种系统化计算模型参数的方法，并根据该方法得到有关模型参 数，计算了O⁶⁺离子与H碰撞系统，所得计算结果在实验误差范围内与实验值很 好符合． 关键词： 双中心原子轨道紧耦合 单俘获截面 模型势 半经典碰撞参数模型 Numer ov算法