Electron capture by large helium droplets
Electron capture by large helium droplets
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DOI：
10.1063/1.476385
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发表时间：
1998-06-08
影响因子：
4.4
通讯作者：
Toennies, JP
中科院分区：
文献类型：
--
作者：
Henne, U;Toennies, JP
在交叉束散射实验中，研究了电子与超临界液体自由射流膨胀中产生的含有多达 10(8) 个原子的大氦液滴的附着。负簇离子是在与来自能量 E-el = 1.0-100 eV 的几乎单能（δ E 近似为 0.25 eV）电子束的电子碰撞时形成的，随后通过静电偏转选择尺寸。根据液滴尺寸，可以解析负离子信号中最多七个不同的共振式最大值，其峰宽 Delta E-1/2 与液滴半径成比例。最低能量峰值在 E-e1 = 1.8-2.3 eV（取决于尺寸），归因于电子的直接定位，随后在 He 液滴内产生气泡。能量高于 20 eV 时的尖锐附加峰可以通过液滴的单次或连续电子激发的阈值来解释，这导致零动能电子，然后该电子也定位在内部气泡中。 (C) 1998 年美国物理研究所。
The attachment of electrons to large helium droplets containing up to 10(8) atoms produced in supercritical liquid free jet expansions has been investigated in a crossed beam scattering experiment. Negative cluster ions were formed in collisions with electrons from a nearly monoenergetic (delta E approximate to 0.25 eV) electron beam with energies E-el = 1.0-100 eV and were subsequently size selected by electrostatic deflection. Depending on the droplet size up to seven distinct resonancelike maxima in the negative-ion signal with peak widths Delta E-1/2 proportional to the droplet radius could be resolved. The lowest energy peak at E-e1 = 1.8-2.3 eV depending on size, is attributed to a direct localization of the electron which subsequently creates a bubble inside the He droplet. The sharp additional peaks at energies above 20 eV are explained by the thresholds for single or successive electronic excitations of the droplets which result in a zero-kinetic-energy electron which then also localizes in an internal bubble. (C) 1998 American Institute of Physics.