Berlin 2001 – scientific programme
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A: Atomphysik
A 13: Photoionisation I (joint session A and MO)
A 13.11: Talk
Thursday, April 5, 2001, 18:15–18:30, H1012
Half-collision model for triple photoionisation of lithium — •Thomas Pattard1,2 and Joachim Burgdörfer3,2 — 1MPI for the Physics of Complex Systems, Nöthnitzer Str. 38, D-01187 Dresden, Germany — 2University of Tennessee, Department of Physics, 401 Nielsen Physics Building, Knoxville, TN 37996-1200, USA — 3Technische Universität Wien, Institut für theoretische Physik, Wiedner Hauptstr. 8-10, A-1040 Wien, Austria
Recently, first measurements of the single photon triple ionisation cross section of lithium have been reported [1]. Accurate numerical ab initio calculations of the full time-dependent dynamics are still limited to systems with no more than two active electrons. Therefore, we recently introduced a half-collision model (HCM) that allows for an approximate treatment of the triple ionisation process by decomposing it into numerically tractable parts, namely a primary photoionisation event and a subsequent (secondary) electron-electron half scattering (a process often referred to as “TS1” in the language of MBPT) [2]. Here, we discuss the application of the HCM to the lithium case. Our results which represent the first calculation of lithium triple ionisation in an energy range where comparison with experiment is possible are in surprisingly good agreement with the experimental data from high energies down to about the cross section maximum, providing clear evidence that the dominant mechanism of the break-up process has been captured by the model. Limitations and possible extensions and refinements of the HCM will also be discussed.
[1] R. Wehlitz et al., Phys. Rev. Lett. 81, 1813
(1998).
T. Pattard and J. Burgdörfer, Phys. Rev. A 63, 020701(R)
(2001).