Interference between One- and Two-Electron Channels in Resonant Inelastic X-Ray Scattering

Abstract

Interference between scattering channels is observed in resonant inelastic x-ray scattering (RIXS) at the Ne K threshold. Final states with |2p-1np⟩ as the main configuration are populated via |1s-1n′p⟩ resonances, where large-amplitude one-electron (n′=n) channels interfere with small-amplitude two-electron (n′≠n) channels. The interference is manifested in an asymmetric line profile where the two-electron resonance occurs in the tail region of the one-electron resonance. In RIXS, this slowly varying tail plays the role of the continuum for the Fano effect. The asymmetric profile is well modeled by means of a single asymmetry parameter, determined by the amplitudes of the scattering channels and the energy separation between the resonances.