Abstract

We have measured the cross sections of elementary processes occurring during collisions of impinging ³He²⁺ particles with kinetic energies in the range 1–100 keV with Xe atoms, which are accompanied with the formation of free electrons and ions in different final charge states: Xeⁿ⁺ (n = 1–6) and He^{(2 – m)+} (m = 0–2). We distinguish between ionization processes, in which the impinging α particle does not change the charge state, and processes of capture of one or two electrons, which lead to the formation of a singly charged helium ion or atom with additional removal of electrons from the xenon atom to the continuum. We have determined the cross sections of formation of free electrons in each of these processes and calculated the contribution of multielectron processes to the formation of free electrons. It is shown that upon a change in the energy of collisions between ³He²⁺ ions from 1 to 100 keV (the velocity of an impinging ion changes from 0.12 to 1.2 a.u.), the mechanism of removal of electrons from the xenon atom changes basically. For low approach velocities of particles, the formation of an autoionization state of the quasi-molecule and its subsequent decay take place. At higher velocities (V > 0.7 a.u.), free electrons are mainly formed because of an abrupt change in the potential energy of electrons when a fast α particle approached the nucleus of the xenon atom.

中文翻译：

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Xe原子与α粒子碰撞中自由电子的形成

摘要

我们测量了Xe原子撞击³ He ²⁺粒子的碰撞过程中发生的基本过程的横截面，该粒子的动能范围为1–100 keV，并伴随着形成不同最终电荷态的自由电子和离子： Xe ^{n +}（n = 1–6）和He ^{（2 – m）+}（m = 0–2）。我们将电离过程（其中撞击的α粒子不改变电荷状态）与捕获一个或两个电子的过程（包括导致单电荷的氦离子或原子的形成以及从氙中额外去除电子的过程）之间进行区分。原子连续体。我们已经确定了每个过程中自由电子形成的横截面，并计算了多电子过程对自由电子形成的贡献。结果表明，当³ He ²⁺之间的碰撞能量发生变化时离子从1 keV到100 keV（撞击离子的速度从0.12到1.2 au改变），从氙原子去除电子的机理基本上发生了变化。对于低的接近速度的粒子，准分子的自电离状态的形成及其随后的衰减发生。在较高的速度（V > 0.7 au）下，自由电子主要是由于当快速的α粒子接近氙原子核时电子势能的突然变化而形成的。