Bond energies of CaAr+, CaKr+, and CaXe+ from resonant two-color photoionization thresholds

Abstract

The ionization thresholds for the metastable Ca(4s4p 3P0)⋅RG(3Π0−,v′′=0) states (RG=Ar, Kr, Xe) have been determined by two-color photoionization via several Ca(4s5s 3S1)⋅RG(3Σ+,v′) intermediate resonance states. From other experimental measurements and ab initio calculations, D0[Ca(4s4p 3P0)⋅RG(3Π0−)]=60±50 cm−1, 120±60 cm−1, and 300±80 cm−1 for RG=Ar, Kr, Xe, respectively, from which D0(CaRG+) are calculated to be 775±50 cm−1, 1244±60 cm−1, and 1811±80 cm−1 for Ar, Kr, Xe, respectively. Bonding in the CaRG+ ions is discussed and compared to the bonding in the analogous BeAr+, MgRG+, and BaAr+ ions.