4:00 PM–4:00 PM, Thursday, May 19, 2005
Burnham Yates Conference Center - Lancaster 4:00-6:00 pm
Juan J. Carrera
Shih-I Chu
(Department of Chemistry, University of Kansas, Lawrence, Kansas 66045)
Xiao-Min Tong
(Physics Department, Kansas State University, Manhattan, Kansas 66506)
We present an \textit{ab initio} nonpertubative investigation of the mechanisms responsible for the production of very high-order harmonic generation (HHG) from Ar atoms and Ar$^{+}$ ions by means of the self-interaction-free time dependent density functional theory recently developed [1]. Further, by introducing an effective charge concept, we can study at which laser intensity the contribution to the high-energy HHG from Ar$^{+}$ ions precede over the Ar atoms. Comparing the HHG behavior from Ar atoms and Ar$^{+}$ ions in super intense laser field, we conclude that the high energy HHG observed in the recent experiment [2] originated from the ionized Ar atoms. [1] J.J. Carrera, S.I.Chu and X.M.Tong, Phys. Rev. A (submitted) [2] Gibson, et. al., PRL 92, 033001 (2004)