Two-center interference in fast proton-H2-electron transfer and excitation processes
Two-center interference in fast proton-H2-electron transfer and excitation processes
复制标题
快速质子-H2-电子转移和激发过程中的双中心干涉
DOI：
10.1103/physreva.72.050703
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发表时间：
2005
影响因子：
2.9
通讯作者：
H. Schmidt
中科院分区：
文献类型：
--
作者：
K. Støchkel;O. Eidem;H. Cederquist;H. Zettergren;P. Reinhed;R. Schuch;C. Cocke;S. Levin;V. Ostrovsky;A. Kälberg;A. Simonsson;J. Jensen;H. Schmidt
本论文的主题是对离子-原子碰撞中电子转移过程的实验研究，其速度明显高于原子或分子束缚态中电子的典型轨道速度。所采用的实验技术将重离子储存环的高束强与配备反冲离子动量谱仪的超音速气体喷射靶结合在一起。在从氦原子到快质子的单电子俘获中，我们第一次实现了运动学机制和Thomas转移机制的完全分离，并能够在比以前更详细的水平上与许多理论结果进行定量比较。对于质子-氦碰撞中的转移电离过程，我们确定了当入射速度Vp足够高时，Thomas转移电离截面的速度依赖性为预期的Vp-11。此外，我们还确定了在第一个电子在运动俘获过程中转移的情况下，第二个电子从氦中脱离的依赖于速度的几率。最后，我们考虑了质子和氢分子之间的碰撞。在这里，我们发现当入射粒子的方向与靶分子的核间轴夹角变化时，转移和激发过程的截面有很大的变化。这种变化可以解释为与分子的两个不可区分的原子中心相关的量子力学干涉的结果。
The subject of this thesis is experimental studies of electron-transfer processes in ion-atom collisions at velocities significantly higher than typical orbital velocities of electrons in bound states of atoms or molecules. The experimental technique applied combines the high beam intensity of heavy-ion storage rings with a supersonic gas-jet target equipped with a recoil-ion-momentum spectrometer. In singleelectron capture to fast protons from helium atoms, we have for the first time achieved a complete separation of the kinematic and Thomas transfer mechanisms and are able to perform a quantitative comparison with the many theoretical results on a much more detailed level than what was previously possible. For the process of transfer ionization in proton-helium collisions we have determined the velocity dependence of the Thomas transfer ionization cross section to be the expected vp-11 when the projectile velocity, vp, is sufficiently high. Further, we have determined the velocity-dependent probability for shake-off of the second electron from helium provided that the first one is transferred in a kinematic capture process. Finally, we have considered collisions between protons and hydrogen molecules. Here we have found a strong variation in the cross section for transfer and excitation processes when the angle between the direction of the incoming projectile and the internuclear axis of the target molecule is varied. The variation can be explained as a result of quantum mechanical interference related to the two indistinguishable atomic centers of the molecule.