  We report on kinematically complete measurements and ab initio
non-perturbative calculations of double ionization of He and H2 by a single 800
eV circularly polarized photon. We confirm the quasifree mechanism of
photoionization for H2 and show how it originates from the two-electron cusp in
the ground state of a two-electron target. Our approach establishes a new
method for mapping electrons relative to each other and provides valuable
insight into photoionization beyond the electric-dipole approximation.
