Photodouble ionisation of the ns-2np6(1Se) state of rare gases

P. BOLOGNESI, S. OTRANTO, C. R. GARIBOTTI, R. FLAMMINI, G. ALBERTI AND L. AVALDI

Caims, Australia

Conferencia; XIV International Conference on Vacuum Ultraviolet Radiation Physics; 2004

The ejection of two electrons of an atom by absorption of a single photon, i.e. the photodouble ionization (PDI), is one of the fundamental few body processes in atomic physics. The archetypal system to study this process is the HE atom, because the final doubly charged ion state has the simples 1^S^e symmetry and therefore the final state of the electron pair is of pure 1^P^o symmetry. A similar conidition can be found in the PDI of the s orbital of heavier rare gases, the only difference being that now the two s-electrons are ejected from an inner-valence shell. In the present contribution, we report on recent measurements of the triple differential cross section (TDCS) of the He^2+ (1s^-2), Ne^2+(2s-2), Ar2+(3s-2) and Xe^2+(5s-2) at ~20 eV above their respective double ionization thresholds, in equal energy sharing condition and perpendicular geometry. The aim of the experiment is to investigate whether the TDCS is purely determined by the symmetry of the final ionic state and the configuration of the electron pair or the internal structure fo the residual ion plays a role. The results are compared with the recentrly introduced SC3 model [1] which can be used to study targets different from He since it allows an easy implementation with different initial state wave functions. [1] S. Otranto and C. R. Garibotti, Eur. Phys. J. D 21, 285 (2002).