The Yellow Excitonic Series of Cu2O Revisited by Lyman Spectroscopy

Abstract : We report on the observation of the yellow exciton Lyman series up to the fourth term in Cu2O by time-resolved mid-infrared spectroscopy. The dependence of oscillator strength on the principal quantum number n can be well reproduced using the hydrogenic model including an AC dielectric constant, and precise information on the electronic structure of the 1s exciton state can be obtained. A Bohr radius a1s=7.9 Å and a 1s–2p transition dipole moment µ1s–2p=4.2 eÅ were found.