A determination of the ionization threshold for the Mg(3s3p 3P0) · Ar(3Π0−) metastable state: The bond energy of MgAr+

The ionization threshold for the metastable Mg(3s3p 3P0) · Ar(3Π0−) state has been determined to be 38744 ± 5 cm−1 by two-color photoionization via Mg(3s4s 3S1) · Ar(3Σ+, ν′) resonance states. From several experimental measurements and an ab initio calculation, D0(Mg(3s3p 3P0) · Ar(3Π0−)) = 160 ± 40 cm−1, from which D0(MgAr+) is calculated to be 1237 ± 40 cm−. This value is consistent with, but more accurate than, previous experimental and ab initio estimates of D0(MgAr+).