Mg 3pns and 3pnd (J=1) autoionizing series.

Abstract

The Mg 3{ital pns} ({ital n}=10--18) and 3{ital pnd} ({ital n}=9--40) doubly excited {ital J}=1 autoionizing states have been observed experimentally using an isolated-core excitation method with stepwise laser excitation. Linearly polarized laser light excites the 3{ital pnd} {ital J}=1 and {ital J}=3 states, as well as the 3{ital pns} {ital J}=1 states. Our previous study of the {ital J}=3 states enables the {ital J}=1 states in the 3{ital pnd} spectra to be identified. We have also calculated the spectra from a reaction matrix, and the agreement between theory and experiment is generally excellent. Differences between the {ital J}=1 and {ital J}=3 features are discussed and qualitatively explained in terms of semiclassical arguments. Additionally, energies of the 3{ital sns} {sup 1}{ital S}{sub 0} ({ital n}=11--22) Rydberg levels are reported.