Localization of inner-shell photoelectron emission and interatomic Coulombic decay in Ne2

We used cold target recoil ion momentum spectroscopy (COLTRIMS) to investigate the decay of Ne-2 after K-shell photoionization. The breakup into Ne1+/Ne2+ shows interatomic Coulombic decay (ICD) occurring after a preceding atomic Auger decay. The molecular frame angular distributions of the photoelectron and the ICD electron show distinct, asymmetric features, which imply localization of the K-vacancy created at one of the two atomic sites of the Ne-2 and an emission of the ICD electron from a localized site. The experimental results are supported by calculations in the frozen core Hartree-Fock approach.