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Excited state distribution and spin-effects in strong-field excitation of neutral Helium

Zimmermann, Henri; Eilzer, Sebastian; Eichmann, Ulli

Inst. Optik und Atomare Physik

We investigated the principal quantum number n distribution of excited states resulting from the interaction of Helium with strong, short laser pulses. We find excellent agreement with predictions of the semiclassical frustrated tunneling ionization (FTI) model [1] as well as fully quantum mechanical calculations. Furthermore, the excitation process directly populates triplet excited states due to the breakdown of the Russel-Saunders coupling scheme for high orbital angular momentum l states of Helium, which are predominantly populated in the strong laser field.