One- and two-photon single ionization of helium: Resolving the role of individual decay channels and resonance states |
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| Vera Neimanns | |
| Universität Freiburg | |
| We combine the method of complex rotation and Floquet theory to analyze the multiphoton ionization of helium atoms in strong laser fields. We focus on 1D Zee helium to highlight the methods that allow us to extract the partial decay rates associated with various decay channels. In the regime of one-photon single ionization, we study the dependence of the partial rates associated with the singly ionized He+ states on the field frequency. We show that the electron-electron interaction provides couplings to higher single-ionization continua. Finally, we examine two-photon single-ionization processes, and analyze the role of the internal electronic structure of the atom, specifically the signature of resonant coupling to intermediate bound states on the decay rates. |