Double photoionization of He near a polarizable surface

We calculate the differential cross section of the direct double photoionization of He physisorbed on a polarizable surface. By including the influence of the surface potential in the correlated two-electron final-state wave function, we show that the differential cross section carries detailed information on the electronic correlations at the surface. In particular, photoemission along opposite directions, which is prohibited in the free space, is allowed if the surface potential is long ranged. © 1999 The American Physical Society.