Fingerprints of the nodal structure of autoionizing vibrational wave functions in clusters: Interatomic Coulombic decay in Ne dimer

The removal of an inner-valence electron from neutral neon clusters leads to autoionization and subsequent fragmentation of the cationic clusters in accordance with the interatomic Coulombic decay mechanism discovered recently. Using non-Hermitian quantum scattering theory we investigate this process in detail for the Ne dimer. We show that a pronounced structure can be observed when measuring the autoionizing electron or the Ne+ kinetic energy distributions. This phenomenon is associated with the properties of the vibrational autoionizing resonance states of the electronically excited cationic dimer. By suppressing coherence among the different vibrational autoionizing resonances, or by selectively exciting one of them, the structures in the kinetic energy distributions become more pronounced. It is demonstrated that these structures reflect the nodal structure of the wave functions of the autoionizing vibrational states most populated by the initial ionization of the neutral neon dimer. In a coherent decay we encounter substantial interference effects, but the nodal pattern of the corresponding wave functions is still present. The kinetic energy distributions are generally very sensitive to details of the potential energy curves of clusters. (C) 2001 American Institute of Physics.