Inner-shell ionization of rotating linear molecules in the presence of spin-dependent interactions: Entanglement between a photoelectron and an Auger electron

This paper reports results of a theoretical study of angle- and spin-resolved photo-Auger electron coincident spectroscopy in the form of entanglement between these two particles emitted from a linear molecule. First, we develop an expression for a density matrix needed for studying spin-entanglement between a photoelectron and an Auger electron. In order to properly represent the molecular symmetries, nuclear rotation, and the spin-dependent interactions (SDIs), we have used symmetry adapted wavefunctions in Hund's coupling scheme (a) for all the species participating in this two-step process. This expression shows that spin-entanglement in a photo-Auger electron pair in the presence of SDIs very strongly depends upon, among other things, polarization of the ionizing radiation, directions of motion and of spin polarization of two ejected electrons, and the dynamics of photoionization and of Auger decay. We have applied this expression, as an example, to a generic linear molecule in its J0, M0 = 0 state. This model calculation clearly brings out the salient features of the spin-entanglement of a photo-Auger electron pair in the presence of the SDIs. (authors)