Wavelength-driven photoelectron momentum tilt in XUV Ionization

Abstract

We investigate how atomic structure influences photoelectron momentum distributions (PMDs) in single-photon ionization by a linearly polarized extreme-ultraviolet (XUV) pulse. We demonstrate that the PMD tilt is governed not only by the magnetic quantum number but also by the radial structure of the bound atomic orbital. While neon exhibits a smooth wavelength dependence of the PMD tilt, argon displays a non-monotonic behavior characterized by suppression and reversal of the tilt at a critical wavelength. A partial-wave analysis reveals that this behavior arises from interference between $s$- and $d$-wave channels, with the reversal originating from a minimum in the $d$-wave radial dipole matrix element induced by the radial node in the argon 3p orbital. We further show that atomic interferometric circular dichroism (AICD) serves as a sensitive probe of this effect. These findings establish a direct link between the radial wavefunction structure and observable momentum-space asymmetries, highlighting the wavelength-dependent rotation and the suppression of the PMD tilt as signatures of radial-node-induced Cooper-like suppression in the $d$-wave channel of argon.