A determination of the ionization threshold for the Mg(3s3p P-3(0))center dot Ar((3)Pi(0-)) metastable state: The bond energy of MgAr+

The ionization threshold for the metastable Mg(3s3p (3)p(0-)). Ar((II0-)-I-3) State has been determined to be 38744 +/- 5 cm(-1) by two-color photoionization via Mg(3s4s S-3(1)). Ar((3) Sigma(+), v') resonance states. From several experimental measurements and an ab initio calculation, D-0(Mg(3s3p (3)p(0)). Ar((II0-)-I-3)) = 160 +/- 40 cm(-1), from which D-0(MgAr+) is calculated to be 1237 +/- 40 cm(-1). This value is consistent with, but more accurate than, previous experimental and ab initio estimates of D-0(MgAr+).