Long-range electron correlation in dissociative double ionization of argon dimers

We experimentally investigate long-range electron-electron correlation across the two atomic sites of an argon dimer in its dissociative double ionization induced by a linearly polarized 400-nm femtosecond laser field. The correlation between the two electrons, ionized at two atomic sites, is revealed through analysis of the joint kinetic energy spectra and the momentum distributions. Notably, one of the two electrons exhibits a pronounced redshift in the low-kinetic-energy region, in contrast to the electron energy spectrum observed in single ionization of argon dimers. This distinctive spectral feature is corroborated by theoretical simulations, which attribute the redshift to the differing intensity dependence of the kinetic energy distributions of the two electrons, as well as to the influence of electron-electron correlation during the ionization process.