Evidence for a Molecule-Rotation-Dependent Spin Polarization Transfer Mechanism in the Photon-Induced Autoionization of HCl and DCl

High resolution spectra of the angle-integrated photoelectron spin polarization, after excitation of HCl and DCl with circularly polarized laser radiation, reveal pronounced rotational autoionization structures. The data, interpreted in terms of Rydberg series converging to limits with different ionic angular momenta of the ${}_{}{}^2{}_{}{}^{}\Pi _{1/2}^{}{}_{}{}^{}$ fine structure component, clearly indicate a systematic dependence of the sign of the spin polarization on the rotation of the molecular ion core. Application of the current theoretical model leads to consequences for the angular momentum transfer in the autoionization process.