Near-threshold two-photon double ionization of Kr in the vacuum ultraviolet
We report angle-resolved measurements on photoelectrons emitted upon near-threshold two-photon double ionization (TPDI) of Kr irradiated by free-electron laser (FEL) pulses. These photoelectron angular distributions (PADs) are compared with the results of semirelativistic R-matrix calculations. As reported by Augustin et al. [Phys. Rev. A 98, 033408 (2018)10.1103/PhysRevA.98.033408], it is found t