Bond energies of MgKr+ and MgXe+ from resonant two-color photoionization thresholds

The ionization thresholds for the metastable Mg(3s3p 3P0)⋅RG(3Π0−,v′′=0) states (RG=Kr,Xe) have been determined by two-color photoionization via several Mg(3s4s 3S1)⋅RG(3Σ+,v′) intermediate resonance states. From other experimental measurements and ab initio calculations, D0(Mg(3s3p 3P0)⋅RG(3Π0−))=250±80 cm−1 and 500±150 cm−1 for RG=Kr,Xe, respectively, from which D0(MgKr+) and D0(MgXe+) are calculated to be 1891±80 cm−1 and 2848±150 cm−1. Bonding in the MgRG+ ions is discussed and compared to the bonding in the analogous NaRG+ and AlRG+ ions.