Interatomic Coulombic decay following Ne 1s Auger decay in NeAr

Using momentum-resolved electron-ion multicoincidence spectroscopy, we have investigated interatomic Coulombic decay (ICD) in the heteronuclear NeAr dimer following Ne 1s Auger decay. The measured intensity ratio for the three ICD transitions Ne2+(2s-12p-11P)Ar to Ne2+(2p-21S)-Ar+(3p-1), Ne2+(2s-12p-11P)Ar to Ne2+(2p-21D)-Ar+(3p-1), and Ne2+(2s-12p-13P)Ar to Ne2+(2p-23P)-Ar+(3p-1) reasonably agree with predictions. The kinetic energy release distribution for the fragmentation to Ne2+(2p-21D)-Ar+(3p-1) after the ICD transition from singlet Ne2+(2s-12p-11P)Ar state, which is a mirror image of the kinetic energy distribution of the emitted ICD electrons, suggests that the corresponding ICD rate is roughly two times lower than predicted by ab initio calculations.