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A: Fachverband Atomphysik

A 19: Photoionization

A 19.6: Vortrag

Dienstag, 18. März 2014, 15:30–15:45, BEBEL E42

Molecular hydrogen in strong laser fields: breakdown(s) of the fixed-nuclei approximation — •Johann Förster and Alejandro Saenz — AG Moderne Optik, Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany

We investigate the effect of nuclear vibration on the ionization behaviour of molecular hydrogen by a direct solution of the time-dependent Schrödinger equation. For this purpose, our six-dimensional configuration-interaction method to solve the electronic Schrödinger equation of molecular hydrogen in strong laser fields [1, 2] is extended to include molecular vibration. The results obtained within the correlated treatment of electronic and vibrational motion are compared to those stemming from the fixed-nuclei approximation (FNA; i.e. the solution of the electronic Schrödinger equation only for the equilibrium geometry). We show that the FNA breaks down for certain laser parameters in the multiphoton and quasistatic regimes. For example, the total ionization yield can differ from the "full" treatment by several orders of magnitude. The reasons for these complete breakdowns of the FNA are explained and it is shown that other very simple (and "useful") approximations still agree surprisingly well with the "full" treatment.

References
[1] M. Awasthi, Y. V. Vanne and A. Saenz, J. Phys. B 38, 3973 (2005).
[2] Y. V. Vanne and A. Saenz, Phys. Rev. A 82, 011403(R) (2010).