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Physical Review Letters Publishes Progress of PKU Research Group

Peking University, Beijing, May 26, 2010: Recently, a cooperative research conducted by 3 scholars, PKU Researcher Liu Yunquan, Prof. Gong Qihuang from the Femtosecond Photophysical and Optoelectronics Research Group, Researcher Liu Jie from the Beijing Institute of Applied Physics and Computational Mathematics, and Prof. Ullrich from the German Max-Plunk Institute of Nuclear Physics has unprecedentedly  studied the correlation problem of laser intensity in the vicinity of atomic double ionization threshold by experiment. By using high-power femtosecond laser and cold target recoil ion momentum spectrometer device, they have discovered that atomic structure has significant influences on the correlation behavior of the non-sequence double ionized electron.

 

This debut research contributes to the understanding of the nature of correlative behaviors of atoms, molecules and electrons and multi-body behaviors of the strong-field quantum. The research has been published on the resent issue of Physical Review Letters (104, 173002 (2010)). Their research is funded by 3 projects: the Innovative Research Group, the Outstanding Youth Fund and the National Key Basic Research Program (973).

 

Taken the contribution of the excited state of monovalent ions into account, they suggest the first analytical model of atomic double ionization threshold in the laser field. The double ionized Ne electrons are emitted neck-to-neck in the laser polarization plane (so-called association), while the double ionized Ar electrons are emitted back-to-back (so-called anti-association). Their theory has taken both the multiple collisions of electrons in laser field and the tunnel ionization process after the collisions into account, which successfully explained the anti-associative phenomenon of the Ar atom. But for the Ne atom, the major mechanism of electronic associative phenomenon is the single Collin in the laser field, because its higher excited state of monovalent ions inhibits the tunnel electronic mechanism.

 

Translated by: LI Xiaomeng

Edited by: Jennifer Yan

Source: PKU News (Chinese)