共查询到20条相似文献,搜索用时 78 毫秒
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采用位置灵敏探测和飞行时间技术测量了等电荷态离子C^q 、N^q 、O^q 、Ne^q (q=4,5,6,7)与He原子碰撞中,转移电离截面与单电子俘获截面的比值Ro研究了相同q入射的情况下,R与入射离子核电荷数Z的依赖关系。在统计蒸发模型的基础上对实验结果进行了解释。 相似文献
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采用位置灵敏探测和飞行时间技术测量了等电荷态离子Cq+、Nq+、Oq+、Neq+(q=4,5,6,7)与He原子碰撞中,转移电离截面与单电子俘获截面的比值R.研究了相同q入射的情况下,R与入射离子核电荷数Z的依赖关系,在统计蒸发模型的基础上对实验结果进行了解释. 相似文献
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高电荷态离子与原子碰撞激发原子碰撞物理实验是在研究微观粒子的结构、能级、碰撞过程、能量输运过程的基础上发展起来的.通过粒子与原子的碰撞,使我们对原子的内部结构有更进一步的了解.例如:卢瑟福由α粒子的碰撞实验发现原子中心有一个核,从而他提出了核式原子模... 相似文献
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采用位置灵敏探测和飞行时间技术研究了高电荷态Xe离子(q=15,17,19,21,23)与He原子碰撞中双电子转移截面与单俘获截面比随入射离子电荷态的变化规律.提出一步过程假定,对扩展的经典过垒(ECB)模型进行了修正,利用修正模型计算得到的单、双电子转移绝对截面与Andersson等人和Selberg等人的实验结果符合得很好,所得截面比与本实验得到的双电子转移截面与单电子俘获截面符合得比较好. 相似文献
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双电荷离子Ar~(2 )和He、Ne原子碰撞中,存在着三种碰撞激发过程,一是双电子俘获激发过程,二是单电子俘获激发过程,三是直接激发过程。实验用光学多道分析系统(OMA)对这些过程进行了光学测量,得到了ArⅠ、ArⅡ、NeⅠ、NeⅡ、HeⅠ、HeⅡ谱线的发射截面,并对这些发射截面进行了比较,发现在入射离子速度相同的情况下,Ar~(2 ) Ne碰撞体系的发射截面要比Ar(2 ) He碰撞体系的大。OMA的光谱波长范围是200—800um。入射离子Ar(2 )的能量范围是140—340keV。 相似文献
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对在北京大学技术物理系核物理与核技术实验1.7MV串列加速器上进行的有关离子原子碰撞内壳层电离机制的研究进展作了简介。 相似文献
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报道Ar^q Ne(q=8,9,11,12)碰撞体系中多电子转移过程,得到了多组实验测量电荷交换截面数据,讨论入射离子电荷交换截面、反冲离子产生截面与入射离子电荷态、能量以及散射离子电荷态的关系,并且将实验结果与Ar^q Ar碰撞体系进行对比研究。在修正分子库仑过垒模型的基础上,对实验现象做了合理的解释。 相似文献
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利用冷靶反冲离子动量谱仪,对低能He2+-He碰撞反应中产生的反冲靶离子和炮弹离子进行了符合测量,根据反冲靶离子的动量,研究了转移电离过程中的电荷转移机理.实验结果表明:在20—40 keV能量范围内,靶原子上的一个电子俘获到炮弹离子的基态,另一个电子直接发射到靶的连续态的直接电离及另一个电子俘获到炮弹离子的连续态的过程(ECC)是最主要的转移电离机理,且ECC过程主要发生在大碰撞参数条件下;炮弹离子俘获两个电子处在双激发态的自电离过程的贡献很小.
关键词:
冷靶反冲离子动量谱仪
转移电离机理
离子原子碰撞 相似文献
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吴英 《原子与分子物理学报》2003,20(2):159-162
反冲离子飞行时间-散射离子位置灵敏符合技术及多参数获取系统测量了2 MeV~8 MeV的氯离子撞击氦原子,伴随氯离子电子损失过程氦的双、单重电离相对截面比;及氦原子被电离伴随的氯离子的双、单电子损失相对截面比.对测量结果进行了分析讨论. 相似文献
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Investigation of the transfer ionization process in collisions of partially stripped ions on He 下载免费PDF全文
In this paper a projectile ion-recoil ion coincidence
technique is used to investigate the transfer ionization processes
in collisions of 0.22--6.30~MeV C^{q + } ions and 0.25--6.35~MeV
O^{q + } ions (q=1, 2, 3, 4) with the He atom separately. The cross
section ratio f of transfer ionization to single electron transfer
is measured, and the dependence of f on both charge state q and
energy E of the projectiles is investigated. The
electron-structure and the mechanisms leading to transfer ionization
affect the dependence of f on q and E. Our measurements, along
with other data published previously, suggest a similar dependence
of f on charge state and energy of projectile for partially
stripped ions over a large energy range. The maximum value of f is
approximately 0.17q^{0.60}; the energy corresponding to maximum
f is about 160q^{0.60}~keV/u. 相似文献
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Projectile angular-differential cross sections for single electron transfer in fast He~+-He collisions 下载免费PDF全文
《中国物理 B》2015,(3)
The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singly positive charged helium ions with helium atoms in their ground states. The formalism satisfies the correct boundary conditions. The influence of the dynamic electron correlations on the cross sections is studied by considering the inter electronic interactions in the complete perturbation potentials in post form. Also, the sensitivity of the cross sections to the static electronic correlations is studied by using the single-zeta and the highly correlated Byron–Joachain wave functions to describe the initial bound state of the active electrons. The obtained results for the energy range of 40–5000 ke V/amu are reported and compared with other three- and four-body theoretical data and available experimental measurements. The comparison leads us to discuss the validity of the applied approach and survey the interaction effects on the cross sections by recognizing the electron–electron interaction. Particularly, for differential cross sections, the comparison of the present four-body method with the experiment shows that the agreement is not as good as that for its three-body version. 相似文献
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基于多组态Dirac-Fock理论方法和冲量近似, 对Xe54+与Xe在197 MeV/u碰撞能量下, 炮弹离子的俘获及退激发过程进行了理论研究. 计算了炮弹离子从中性靶原子俘获一个电子到nl (n=1, 2, 3, 4, 5; l=s, p, d) 轨道上的辐射电子俘获截面和相应的辐射光子能量, 以及俘获末态退激发辐射跃迁的能量和概率. 结合这些计算结果, 进一步模拟了碰撞产生的炮弹离子的退激发X射线谱的结构, 并与兰州重离子加速器装置上的最新实验观测结果进行了比较, 符合得很好. 相似文献
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126Xeq+轰击Al表面产生的原子和离子光谱线 总被引:1,自引:1,他引:0
报道了高电荷态离子^126Xe^q (6≤q≤30)入射到固体Al表面产生的200~1000nm波段的发射光谱的实验结果。实验表明,在弱束流(nA量级)高电荷态的情况下,通过入射离子与固体靶的相互作用可有效地产生原子和离子的复杂组态间跃迁所形成的可见光波段的特征谱线,而且当入射离子的电荷剥离数超过一临界值后(对Al,q=26),谱线相对强度突然显著增强。根据经典过垒模型COB(The classic over-barrier model),在入射离子的动能较小(~1keV/u)的条件下.高电荷态离子与表面相互作用过程中电子的俘获或转移起着非常重要的作用,通过提高入射离子的电荷态可增强入射离子俘获电子的能力.显著增强激发粒子的光谱线的强度。 相似文献
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Investigation of transfer ionization in collisions of partially stripped carbon ions with helium at low to intermediate velocities 下载免费PDF全文
The ratios of transfer ionization (TI) to single-electron
capture (SC) cross sections have been measured for the
collisions of partially stripped Cq+ ions (q=1--4) with
He. The collision velocity ranges from 0.7 to 4.4v0
(v0 is the Bohr velocity). The projectile-ion and
recoil-ion coincidence technique is used to separate the
processes of TI and SC. The ratios reach the maximum when the
velocity is about 3.7v0 This can be explained
qualitatively based on the two-step mechanism. The experimental
results are also compared with the results calculated using the
classical trajectory Monte Carlo (CTMC) method. The CTMC results
are in agreement with the experimental data basically. The
discrepancies in higher velocity region are interpreted by the
effective charge effect. 相似文献
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We investigate the single-electron loss processes of light charged ions (Li^1+,2+, C^2+,3+,5+, and O^2+,3+) in collisions with helium. To better understand the experimental results, we propose a theoretical model to calculate the cross section of projectile electron loss. In this model, an ionization radius of the incident ion was defined under the classical over-barrier model, and we developed "strings" to explain the processes of projectile electron loss, which is similar with the molecular over-barrier model. Theoretical calculations are in good agreement with the experimental results for the cross section of single-electron loss and the ratio of double-to-single ionization of helium associated with one-electron loss. 相似文献