Multi-ionization of the Cl(2) molecule in the near-infrared femtosecond laser field

The multi-electron ionization and subsequent dissociation of the Cl(2) molecule in a near-infrared femtosecond laser field was investigated via the dc-sliced ion imaging technique. The single charged molecular ions, Cl(2)(+), dissociate from two excited states, (2)Π(u) and (2)Σ(g)(+), with the electrons ionized from the HOMO−1 and HOMO−2 orbital, respectively. For the multi-charged molecular ions, Cl(2)(n+) (n = 2–8), our results showed that the stretch of the inter-nuclear distance benefitted the ionization of the electrons to produce highly-charged molecular ions. In addition, compared with the traditional charge resonance enhanced ionization (CREI) model, the critical distance (R(c)) for the Cl(2) molecule in our experiment was a short range that depended on the charge state rather than a single point.