中国物理B ›› 2011, Vol. 20 ›› Issue (1): 13403-013403.doi: 10.1088/1674-1056/20/1/013403

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

Semiclassical calculation of ionisation rate for Rydberg helium atoms in an electric field

王德华   

  1. College of Physics, Ludong University, Yantai 264025, China
  • 收稿日期:2010-03-04 修回日期:2010-03-28 出版日期:2011-01-15 发布日期:2011-01-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10604045 and 11074104), the University Science and Technology Planning Program of Shandong Province of China (Grant No. J09LA02), and the Discipline Construction Fund of Ludong University of China.

Semiclassical calculation of ionisation rate for Rydberg helium atoms in an electric field

Wang De-Hua(王德华)   

  1. College of Physics, Ludong University, Yantai 264025, China
  • Received:2010-03-04 Revised:2010-03-28 Online:2011-01-15 Published:2011-01-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10604045 and 11074104), the University Science and Technology Planning Program of Shandong Province of China (Grant No. J09LA02), and the Discipline Construction Fund of Ludong University of China.

摘要: The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields, where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields.

Abstract: The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields, where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields.

Key words: ionisation rate, closed orbit theory, core scattering, pulse train

中图分类号:  (Electronic excitation and ionization of molecules)

  • 34.50.Gb
32.80.Fb (Photoionization of atoms and ions)