Relativistic multichannel treatment of the autoionization Rydberg series 3ds(1D2)np 2P1/2o of scandium

In the framework of multichannel quantum defect theory, the energy levels of autoionization Rydberg series of 3ds(1D2)np (n = 13-21) 2P1/2o of scandium (Sc) are calculated from first principles by relativistic multichannel theory, and these calculations are at four levels of approximation, i.e. frozen core approximation, including dipole polarization effects, quadrupole polarization effects and both dipole polarization and quadrupole polarization effects, respectively. The present calculations show that both dipole polarization and quadrupole polarization effects play an important role. The calculation that includes both dipole polarization effects and quadrupole polarization effects agrees well with the experimental data. Furthermore, two perturbed states related to quadrupole polarization effects are found in the energy region of autoionization Rydberg series of 3ds(1D2)np(n = 13-21) 2P1/2o of Sc and assigned based on our calculation.