Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization

Abstract

We report on a kinematically complete measurement of double ionization of helium by a single 1100 eV circularly polarized photon. By exploiting dipole selection rules in the two-electron continuum state, we observed the angular emission pattern of electrons originating from a pure quadrupole transition. Our fully differential experimental data and companion ab initio nonperturbative theory show the separation of dipole and quadrupole contributions to photo-double-ionization and provide new insight into the nature of the quasifree mechanism.

arXiv comment5 Pages, 3 Figures

References in corpus (2)

• Ejection of quasi-free electron pairs from the helium atom ground state by single photon absorption
• Effects of nonzero photon momentum in (γ,2e) processes

Cited by in corpus (6)

• Theory of Subcycle Linear Momentum Transfer in Strong-Field Tunneling Ionization
• Electric Nondipole Effect in Strong-Field Ionization
• Observation of Photoion Backward Emission in Photoionization of He and N2
• Chiral photoelectron angular distributions from ionization of achiral atomic and molecular species
• Multiple photodetachment of atomic anions via single and double core-hole creation
• Revealing the Two-Electron Cusp in the Ground States of He and H2 via Quasifree Double Photoionization