Delayed fragmentation of weakly bound Kr₂⁺

We report the experimental observation of the delayed fragmentation of the weakly bound dimer Kr₂⁺ produced through the single ionization of Kr₂ by a femtosecond laser field. The observed time delay between ionization and fragmentation, which reflects the survival time of the resulting Kr₂⁺, is measured on the microsecond timescale. A detailed analysis of the kinetic energy releases of the ejected fragments and photoelectrons suggests that this delayed fragmentation arises from the radiative decay of the long-lived Kr₂⁺, transitioning from the bound state II(1/2u) to the repulsive state I(1/2g).