Photoionization spectroscopy of CuKr

An electronic spectrum for the van der Waals complex CuKr is observed. This weakly bound system is produced by laser vaporization of a copper sample in a pulsed supersonic molecular beam source, using krypton in the expansion gas. Spectra are obtained using mass-resolved resonant two-photon ionization spectroscopy (R2PI) for all the different CuKr isotopomers. Two electronic states are observed, corresponding to the copper atomic 2P12,32 ← 2S12 transitions with origins at 29102 and 29239 cm−1. Dissociation energies for both the ground 2Σ12 state (408 cm−1)and excited 2Π12,32 states (1842 and 2009 cm−1) are determined.