Multiphoton Ionization Spectroscopy of the Alkaline Earths

Abstract

Many aspects of the electronic structure of many-electron atoms are still not well understood. In many-electron atoms, the Coulomb repulsion and spin-orbit coupling effects between electrons strongly influence the nature of the electronic states. The one-electron picture, where each electron is viewed as moving in a well-defined orbit, independent of the motion of the other electrons, breaks down when these effects are strong enough. This has hindered efforts to identify and classify the states of many-electron atoms with one-electron labels. We have shown how multiphoton ionization spectroscopy provides us with new spectroscopic data allowing us to identify previously unknown states of alkaline earth atoms and how the Coulomb repulsion of the two outer electrons may be taken into account via a model based on multichannel quantum defect theory (MQDT).