Theoretical analysis of ionic autoionization spectra of lanthanum in the energy region 90 213–91 800 cm−1

In the framework of multi-channel quantum defect theory, eigenquantum defects μα and transformation matrices Uiα of La+ are calculated from first principles by relativistic multi-channel theory, while the dipole matrix elements Dα are obtained by fitting with experimental data. Then the ionic autoionization spectra of lanthanum via the intermediate state [Xe]5d6d3F2 in the energy region 90 213–91 800 cm−1 are obtained. Experimental peaks are classified and clearly assigned by comparing with the corresponding experimental spectra. More specifically, two autoionization Rydberg series converging to La2+ 5d5/22D5/2 and several states converging to higher-lying states of La2+ are found and assigned.