Spin scattering of 1S orthoexcitons in Cu2O

The interaction within the threefold degenerate Gamma (+)(5) 1S-orthoexcito n of the yellow series in Cu2O leads to a population redistribution among t he orthogonal states. We report new experiments which allow a more direct a nalysis of this process. The structure of the interaction is analyzed and t he resulting selection rules are found to be in good agreement with the exp eriments. Furthermore, it is shown that propagation effects dominantly infl uence the population decay. This new analysis leads to different relaxation times as compared to previous results. (C) 2000 Elsevier Science Ltd. All rights reserved.