SAMOP 2023 – scientific programme

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MO: Fachverband Molekülphysik

MO 20: Poster III

MO 20.8: Poster

Thursday, March 9, 2023, 16:30–19:00, Empore Lichthof

Analysis of statistical moments -- a new technique to find Legendre coefficients in photoelectron distributions with increased precision — •Simon Ranecky, Sagnik Das, Sudheendran Vasudevan, Tonio Rosen, Han-gyeol Lee, Jayanta Ghosh, Hendrike Braun, Arne Senftleben, and Thomas Baumert — Uni Kassel, Experimentalphysik III

The ionisation of isotropically aligned molecules with linear or circular polarized light leads to a characteristic distribution of the photoelectrons. The radial part of the distribution relates to the energy of the photons and the ionisation potential of the molecules. The angular part can be described by Legendre polynomials of the order up to twice the number of photons involved in the ionisation [1].

In velocity map imaging, which we use to detect photoelectrons, the 3d electron distribution is projected electrostatically on a phosphorous screen. The right orientation of the spectrometer leads to no information loss in the Abel-projection, but an Abel-inversion like rbasex [2] is necessary to find out the distribution of the Legendre coefficients.

As an alternative way to retrieve the Legendre coefficients, the centroid and higher moments of the photoelectron projection can be used. With the calculated moments of single Legendre polynomials, a linear system of equations can be compiled that makes the Legendre coefficients accessible. For simple photoelectron distributions, we will demonstrate smaller uncertainties as compared to rbasex.

[1] Yang, Phys. Rev. 74, 764; Dixit et al., J Chem. Phys, 82, 3546

[2] Hickstein et al., Rev. Sci. Instrum. 90, 065115