Multiphoton ionization of Mg in the wavelength region of 300–214 nm

The results of an experimental spectroscopic study of the 3pnp ${}_{}{}^1{}_{}{}^{}$ ${\mathit{S}}^{\mathit{e}}$ (n=3–6) and 3p4f ${}_{}{}^1{}_{}{}^{}$ ${\mathit{D}}^{\mathit{e}}$ autoionizing states of Mg populated via two-photon absorption are presented and compared with those of different recent theoretical calculations. The study includes excitation spectra and electron angular distributions resulting from the autoionization decay. Photoelectron angular distributions following resonantly enhanced multiphoton ionization via the 3s3p ${}_{}{}^1{}_{}{}^{}$P, 3s4s ${}_{}{}^1{}_{}{}^{}$S, and 3s3d ${}_{}{}^1{}_{}{}^{}$D intermediate states are also reported and discussed. A strong observed single-photon excitation of the 3s3d ${}_{}{}^1{}_{}{}^{}$D state via an electric quadrupole transition is also presented.