Freiburg 2024 – scientific programme

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A: Fachverband Atomphysik

A 16: Poster II

A 16.1: Poster

Tuesday, March 12, 2024, 17:00–19:00, Tent B

Orientation dependent ionization yield of molecules — •Paul Winter and Manfred Lein — Leibniz University Hannover

The ionization rate and thus the yield is a central property in strong field ionization of molecules. The ionization rate of a diatomic molecule depends on the relative angle between the electric field and the molecular axis at the moment of ionization.

In simulations it is possible to obtain the orientation dependent quasistatic ionization rate by solving the time-dependent Schrödinger Equation (TDSE) with a static electric field for different molecular orientations and analyzing the emerging steady state. In a typical strong-field experiment, however, finite laser pulses are used and the electron yield is measured for a whole pulse, which raises the question whether the quasistatic rates can be accurately measured. Linearly polarized pulses mix the ionization of two opposite directions, thus they cannot reproduce the quasistatic rate. On the other hand, we show that also circularly polarized fields can lead to qualitatively wrong results.

To solve this problem, we propose using two-color ω-2ω fields with either linear or bicircular polarization. To this end, two-dimensional TDSE solutions for HeH⁺ are compared for several different field configurations.

Keywords: molecules; ionization yield; bicircular; two-color; numerical TDSE simulations