Photoemission of pairs of electrons from rare-gas solids

Abstract
By using a new photoelectron-photoelectron coincidence technique, we demonstrate that the absorption of vacuum-ultraviolet photons (20<ħω eV) by rare-gas solids leads to the ejection of pairs of electrons in addition to the well-known single-electron photoemission process. We show that at least two separate processes produce pairs of electrons with a surprisingly high efficiency.