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^-1′1P)Ar to Ne2⁺(2p^-2′1S)-Ar⁺(3p^-1), Ne2⁺(2s^-12p^-1′1P)Ar to Ne2 ⁺(2p^-2′1D)-Ar⁺(3p^-1), and Ne2⁺(2s^-12p^-1′3P)Ar to Ne2 ⁺(2p^-2′3P)-Ar⁺(3p^-1) reasonably agree with predictions. The kinetic energy release distribution for the fragmentation to Ne2⁺(2p^-2′1D)-Ar ⁺(3p^-1) after the ICD transition from singlet Ne2 ⁺(2s^-12p^-1′1P)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.