Two-photon absorption into excited states of excitonic molecules and their inelastic scattering in ${\mathrm{ZnP}}_2$

Excited states of excitonic molecules have been observed by the direct method of giant two-photon absorption in a monoclinic ${\mathrm{ZnP}}_2$ 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.