Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 3: Multi Photon Processes

A 3.10: Vortrag

Montag, 2. April 2001, 18:00–18:15, H1058

Nonsequential ionization in strong laser fields: can meanfield studies be meaningful? — •D. Bauer and F. Ceccherini — Theoretical Quantum Electronics, Darmstadt University of Technology, Hochschulstr. 4a, 64289 Darmstadt

Nonsequential ionization (NSI) is so far the most prominent effect in strong field laser atom interaction where a “single active electron” (SAE) point of view dramatically fails in predicting experimental results. The most successful theoretical approach, capable of reproducing experiment remarkably well, is the so-called “intense field many body S-matrix theory” (IMST) by Becker and Faisal [1]. Full ab initio calculations beyond helium are not feasible even with the most powerful super computers. Therefore a meanfield method such as time-dependent density functional theory (TDDFT), in principle exact, seems a tractable and promising approach. Unfortunately, highly successful density functionals which work well in the time-independent case cannot reproduce NSI [2]. On the other hand, TDDFT-related, although not rigorous methods show NSI [3]. We present results from numerical TDDFT (and TDDFT-related) calculations for He and Ne and discuss the necessary “ingredients” to see NSI in meanfield studies. We compare our results with experiment and related work [4].

[1] A. Becker and F. H. M. Faisal, J. Phys. B 32, L335 (1999), and references therein. [2] M. Petersilka and E. K. U. Gross, Laser Physics 9, 105 (1999). [3] J. B. Watson et al., Phys. Rev. Lett. 78, 1884 (1997). [4] U. Eichmann et al., Phys. Rev. Lett. 84, 3550 (2000).