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Electron removal in collisions of alpha particles with neon dimers is studied using an independent-atom-independent-electron model based on the semiclassical approximation of heavy-particle collision physics. The dimer is assumed to be frozen at its equilibrium bond length and collision events for the two ionâ€"atom subsystems are combined in an impact parameter by impact parameter fashion for three mutually perpendicular orientations. Both frozen atomic target and dynamic response model calculations are carried out using the coupled-channel two-center basis generator method. We pay particular attention to inner-valence Ne(2 s) electron removal, which is associated with interatomic Coulombic decay (ICD), resulting in low-energy electron emission and dimer fragmentation. Our calculations confirm a previous experimental result at 150 keV/amu impact energy regarding the relative strength of ICD compared to direct electron emission. They further indicate that ICD is the dominant Ne+ + Ne+ fragmentation process below 10 keV/amu, suggesting that a strong low-energy electron yield will be observed in the ionâ€"dimer system in a regime in which the creation of continuum electrons is a rare event in the ionâ€"atom problem. [ABSTRACT FROM AUTHOR]

Abstract: The gerade autoionizing Rydberg states of Ne2 have been studied in the range 162000–172000cm−1 by 1+1′ resonant two-photon excitation from the Ne2 X ground state via different vibrational levels of the Ne2 C state. A rotationally resolved part of the spectrum allowed the determination of the potential energy functions of two states of 1g and characters in the vicinity of the Ne(2p6 1S0)+Ne (2p54p′) dissociation limit. The presence of maxima in these potential energy functions is interpreted as originating from a repulsive interaction between the Rydberg electron and the neutral atom. [Copyright &y& Elsevier]

Abstract: Correlated many-particle dynamics in Coulombic systems, which is one of the unsolved fundamental problems in AMO-physics, can now be experimentally approached with so far unprecedented completeness and precision. The recent development of the COLTRIMS technique (COLd Target Recoil Ion Momentum Spectroscopy) provides a coincident multi-fragment imaging technique for eV and sub-eV fragment detection. In its completeness it is as powerful as the bubble chamber in high energy physics. In recent benchmark experiments quasi snapshots (duration as short as an attosecond) of the correlated dynamics between electrons and nuclei have been made for atomic and molecular objects. This new imaging technique has opened a powerful observation window into the hidden world of many-particle dynamics. [Copyright &y& Elsevier]