中国物理B ›› 2016, Vol. 25 ›› Issue (11): 110301-110301.doi: 10.1088/1674-1056/25/11/110301

• GENERAL • 上一篇    下一篇

Fractal dynamics in the ionization of helium Rydberg atoms

Xiulan Xu(徐秀兰), Yanhui Zhang(张延惠), Xiangji Cai(蔡祥吉), Guopeng Zhao(赵国鹏), Lisha Kang(康丽莎)   

  1. 1 College of Physics and Electronics, Shandong Normal University, Jinan 250014, China;
    2 School of Physics, Shandong University, Jinan 250100, China
  • 收稿日期:2016-06-06 修回日期:2016-06-28 出版日期:2016-11-05 发布日期:2016-11-05
  • 通讯作者: Yanhui Zhang E-mail:yhzhang@sdnu.edu.cn
  • 基金资助:

    Project supported by the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM030).

Fractal dynamics in the ionization of helium Rydberg atoms

Xiulan Xu(徐秀兰)1, Yanhui Zhang(张延惠)1, Xiangji Cai(蔡祥吉)2, Guopeng Zhao(赵国鹏)1, Lisha Kang(康丽莎)1   

  1. 1 College of Physics and Electronics, Shandong Normal University, Jinan 250014, China;
    2 School of Physics, Shandong University, Jinan 250100, China
  • Received:2016-06-06 Revised:2016-06-28 Online:2016-11-05 Published:2016-11-05
  • Contact: Yanhui Zhang E-mail:yhzhang@sdnu.edu.cn
  • Supported by:

    Project supported by the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM030).

摘要:

We study the ionization of helium Rydberg atoms in an electric field above the classical ionization threshold within the semiclassical theory. By introducing a fractal approach to describe the chaotic dynamical behavior of the ionization, we identify the fractal self-similarity structure of the escape time versus the distribution of the initial launch angles of electrons, and find that the self-similarity region shifts toward larger initial launch angles with a decrease in the scaled energy. We connect the fractal structure of the escape time plot to the escape dynamics of ionized electrons. Of particular note is that the fractal dimensions are sensitively controlled by the scaled energy and magnetic field, and exhibit excellent agreement with the chaotic extent of the ionization systems for both helium and hydrogen Rydberg atoms. It is shown that, besides the electric and magnetic fields, core scattering is a primary factor in the fractal dynamics.

关键词: self-similarity structure, ionization dynamics, fractal dimension, helium Rydberg atom

Abstract:

We study the ionization of helium Rydberg atoms in an electric field above the classical ionization threshold within the semiclassical theory. By introducing a fractal approach to describe the chaotic dynamical behavior of the ionization, we identify the fractal self-similarity structure of the escape time versus the distribution of the initial launch angles of electrons, and find that the self-similarity region shifts toward larger initial launch angles with a decrease in the scaled energy. We connect the fractal structure of the escape time plot to the escape dynamics of ionized electrons. Of particular note is that the fractal dimensions are sensitively controlled by the scaled energy and magnetic field, and exhibit excellent agreement with the chaotic extent of the ionization systems for both helium and hydrogen Rydberg atoms. It is shown that, besides the electric and magnetic fields, core scattering is a primary factor in the fractal dynamics.

Key words: self-similarity structure, ionization dynamics, fractal dimension, helium Rydberg atom

中图分类号:  (Semiclassical theories and applications)

  • 03.65.Sq
34.50.Fa (Electronic excitation and ionization of atoms (including beam-foil excitation and ionization)) 05.45.Pq (Numerical simulations of chaotic systems)