Two-photon absorption into excited states of excitonic molecules and their inelastic scattering inZnP2

Abstract

Excited states of excitonic molecules have been observed by the direct method of giant two-photon absorption in a monoclinic ZnP 2 single crystal. Their origin and comparison with theoretical expectations are discussed. Photoluminescence of thermalized and nonthermalized ''cold'' excitonic molecules was studied under resonant two-photon excitation into their ground and excited states. An alternative mechanism of inelastic scattering of excitonic molecules is suggested.