Nondipole effects in interference patterns of a two-electron wave

Abstract

When the photoionization is described beyond the dipole approximation, the electron in atoms and molecules will experience a spatially dependent light phase. As demonstrated in a recent experiment on one-photon double ionization of ${\mathrm{H}}_{2}$ [S. Grundmann et al., Science 370, 339 (2020)], the resulting phase difference modifies the electron interference pattern. By solving the full-dimensional time-dependent Schr\"odinger equation beyond the dipole approximation, the present work provides corresponding ab initio calculations that have been missing so far, to the best of our knowledge. Due to the two-electron nature of this process, one may wonder about the roles played by the electron-electron correlation in the shifting of the interference fringes. Indeed, we show that the modification of the interference pattern occurs at the two-electron level, which is independent of the energy partition between the two electrons. Our numerical results agree excellently with the prediction of a simple model, in which the entangled electron pair is launched by light with a spatially dependent phase.