Semiclassical Calculation of the Ionization Rate for a Rydberg Hydrogen Atom in a Magnetic Field

De-Hua Wang ； Shao-Hao Cheng

《Chinese Journal of Physics》 53卷5期 (2015/10) Pp. 100402-1-400402-13

https://doi.org/10.6122/CJP.20150805

並列摘要

In the ionization of a Rydberg hydrogen atom in a uniform magnetic field by a short laser pulse, electrons will be emitted from the nucleus and arrive at the detector in a time sequence. The ionization rate of a Rydberg hydrogen atom in a uniform magnetic field is calculated within the framework of the semiclassical theory. The calculation result suggests that the hydrogen atom ionizes by emitting a series of electron pulses, and the ionization rate depends sensitively on the scaled energy of this system. As the scaled energy is far below the classical ionization threshold, there is only a single electron pulse, with an exponentially decaying tail. The classical motion of the electron is regular. With an increase of the scaled energy, the ionization rate curve becomes complicated and a series of electron pulses appear. This is caused by classical chaos, which occurs due to the magnetic field. In addition, the ＂epistrophic self-similarity＂ fractal structure is reflected in the structure of the ionization rate curve. As the hydrogen atom in strong magnetic field is a very simple system and the experimental study is easy and possible, therefore, our theoretical study may guide the experimental study of the chaotic and fractal dynamics of a Rydberg atom in a magnetic field.