Enhanced nondipole effects in low energy photoionization

It is found that electric-dipole-electric-quadrupole E1-E2 interference eff ects at low photon energies, of the order of tens of eV, in photoelectron a ngular distributions can be significant, comparable to, or even larger than , effects at energies of hundreds to thousands of eV, owing to quadrupole a utoionizing resonances. This is illustrated both for Ne 2p photoionization around 51 eV and Ar 3p photoionization around 33 eV, where random phase app roximation with exchange calculations are performed with allowance for corr elations in both dipole and quadrupole channels.