共查询到19条相似文献,搜索用时 218 毫秒
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经典轨迹蒙特卡罗(CTMC)方法是研究离子-原子碰撞系统电荷交换过程的常用方法,广泛应用于天体物理以及实验室等离子体环境下重粒子碰撞过程的研究.本文利用四体碰撞模型(4-CTMC)研究了包括两个束缚电子的四体碰撞过程,通过数值求解四体碰撞系统的哈密顿运动方程,计算了高电荷态入射离子(Li3+,Be4+和O7+)同氦原子在大能量范围的单、双电子电离和俘获截面.H++He碰撞截面的计算中,在50—200 keV/amu的入射能区,4-CTMC的结果几乎重复了实验结果.在高电荷态入射情形下,4-CTMC计算的单电子电离和俘获截面值相较于三体碰撞模型(3-CTMC)在100—500 keV/amu的入射能区内与实验符合更好.尽管4-CTMC和3-CTMC忽略了电子关联,均高估了双电子电离和俘获截面(与实验值相比),但4-CTMC的结果更接近实验. 相似文献
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建立了一套用于研究单价正离子与气体分子碰撞的单电子俘获过程的装置,测量了7.5-30keV能量范围的C+、N+、O+离子与H2分子碰撞单电子俘获截面。对于30keV能量点,我们的实验结果和文献推荐值符合较好,其它能量点尚未见报道 相似文献
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实验用光学多道分析系统(OMA)测量了He2+和Ne,Ar碰撞过程中的发射光谱,结果表明,这些碰撞体系存在着三种激发过程:双电子俘获激发过程、单电子俘获激发过程和直接激发过程。给出了HeI,HeII,NeI,NeII和ArI,ArII谱线的发射截面,并对He2++Ne和He2++Ar两个碰撞体系的发射截面作了一些比较,发现在入射离子速度相同的情况下,后者的发射截面要比前者大得多,并对此进行了定性讨论。OMA的光谱波长范围为200—800nm。入射离子He2+的能量范围为140—340keV。
关键词: 相似文献
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在中能区测量了Cq+(q=1-4)与He,Ne,Ar气体原子碰撞的电子损失截面,计算分析了入射离子损失两个电子与一个电子的总截面比 R21. 单反应道分析无法完全解释所有实验结果,必须同时考虑入射离子的电子损失、电子俘获和靶原子电离各种出射道间的耦合作用. 对于不同靶原子的碰撞,入射离子损失一个电子和两个电子的速度阈值可以由屏蔽和反屏蔽理论解释. 然而,该理论不能完全解释截面比 R21
关键词:
离子-原子碰撞
截面
电子损失 相似文献
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介绍了离子-原子碰撞过程中双微分绝对截面的计算方法.利用符合技术测量了中能区C3++Ne碰撞系统的纯电离微分绝对截面. 将实验结果与多体经典蒙特卡罗方法计算结果进行对比后发现,纯电离截面随入射能量变化的趋势基本一致,对理论与实验产生差异的原因作了分析. 对多重电离的电离机制分析表明:高价态的反冲离子主要来自于俄歇贡献;随着入射能量的升高,电子-电子间的库仑作用也逐渐显现. 此实验方法可以用于相同实验装置上的各种反应出射道的绝对截面测量,入射离子种类及入射离子能量范围将得到拓展.
关键词:
离子-原子碰撞
绝对截面
纯电离 相似文献
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S. Kumari S. N. Chatterjee L. K. Jha B. N. Roy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(2):355-363
H+ impact single and He2+ impact single and double electron
capture cross sections of magnesium atoms have been calculated in the
modified binary encounter approximation (BEA). The accurate expressions of
ion impact sDE\sigma _{\Delta {E}} (cross section for energy transfer
DE\Delta E) and Hartree-Fock momentum distributions of the target
electrons have been used throughout the calculations. On the basis of the
present work it is concluded that inner shell captures by H+ and
He2+ ions incident on magnesium atoms contribute partly to single
electron capture and partly to transfer ionization cross sections. The
calculated He2+ impact double electron capture cross sections of
magnesium are in reasonably good agreement with the experimental
observations. This indicates the success of the present theoretical approach
in study of charge transfer cross sections of atoms as indirect mechanisms do
not interfere with double electron capture processes in this case. 相似文献
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A. Bekstein M. Benhenni M. Yousfi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):153-159
The ion swarm transport coefficients such as reduced mobility, diffusion
coefficients and reaction rates of three water vapour ion clusters
(H2O)
n
H+ (with n = 1, 2 and 3) in N2 and O2 have
been determined from a Monte Carlo simulation using calculated and measured
elastic and inelastic collision cross sections. The elastic momentum
transfer cross sections have been determined from a semi-classical JWKB
approximation based on a rigid core interaction potential model. The
inelastic cross sections have been deduced from the measured ones in the
case of similar ion cluster. Then, the cross sections sets are fitted using
either the measured reduced mobility at low electric field in the case of
(H2O)
n
H+ in N2 or the zero-field mobility calculated
from the Satoh's relation and the measured ones in N2. From the sets of
elastic and inelastic collision cross sections thus obtained in pure N2
and O2, the ion transport and reaction coefficients for
(H2O)
n
H+ are then calculated in dry air and also
extended over a wide range of reduced electric field in N2 and O2.
These ion data are very useful for modelling and simulation of non-equilibrium
electrical discharges more particularly in humid gases at
atmospheric pressure. 相似文献
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Charge-transfer cross sections for H+ + Li and He2++Licollisions were calculated at low to intermediate impact energies. A multistate perturbed-stationary-state method was employed that includes electron translation factors. 相似文献
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Slow ion production cross sections for collisions of H+3 and D+3 ions with H2 and D2 have been measured at collision energies between 100 eV and 500 eV. The values vary from 2 × 10-17 cm2 to 6 × 10-17 cm2. The smaller cross sections for D3 projectiles may be explained as an internal energy effect. 相似文献
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K. Kadota D. Dijkkamp R. Van Der Woude Pan Guang Yan F.J. De Heer 《Physics letters. A》1982,88(3):135-139
We have studied the He2+-Li collision system at laboratory energies between 15 and 150 keV using optical methods. From the measured emission cross sections we derive state-selective capture cross sections for n = 2,3,4 and n ? 5 states of the He+ ions. Our data are consistent with theoretical predictions of Bransden and Ermolaev. The total capture cross sections as evaluated from our emission cross section data, agree very well with the results of McCullough et al. obtained from projectile charge detection measurements. Near 15 keV our emission cross sections for 30.4 nm and 25.6 nm are much larger than those measured previously by Barrett and Leventhal at slightly lower energies. 相似文献