Hannover 2010 – scientific programme
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A: Fachverband Atomphysik
A 28: Attosecond Physics II / Interaction with Strong or Short Laser Pulses III
A 28.7: Talk
Friday, March 12, 2010, 15:30–15:45, F 107
The mechanisms underlying strong field double ionization of argon dimers — •Bastian Manschwetus1, Horst Rottke1, Günther Steinmeyer1, Lutz Foucar2, Armin Czasch3, Horst Schmidt-Böcking3, Reinhard Dörner3, and Wolfgang Sandner1 — 1Max-Born-Institut, Max-Born-Str. 2A, 12489 Berlin, Germany — 2Max Planck Advanced Study Group, Center for FEL Science, 22761 Hamburg, Germany — 3Inst. für Kernphysik, Goethe Univ. Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt, Germany
We investigate double ionization of argon dimers in high intensity ultra-short Ti:Sapphire laser pulses. We find atomic ion pairs from Coulomb explosion of the doubly charged dimer which can be attributed to two-site single ionization, and to one-site single ionized and exited configurations of the dimer which Coulomb explode after electron exchange accompanied by emission of a second electron at short internuclear separation. A possible excitation mechanism for this second channel is tunnel ionization of one electron accompanied by shake-up of a second one. High energy ion pairs are attributed to Coulomb explosion of the double ionized dimer after additional excitation of an electron to a Rydberg state by frustated tunnel ionization [1] or by inelastic scattering excitation of the ion by the returning laser accelerated electron. The dissociation of this exited double ionized dimer ion is similar to Coulomb explosion of a triple ionized dimer until shielding of the charge of the Ar++ ion by the Rydberg electron becomes significant at large internuclear separation.
[1] Eichmann et al. Phys. Rev. Lett. 101, 233001 (2008)