Distribution of Excitonic Molecules under the Giant Two-Photon Excitation in CuCl

Abstract

Line shapes of the luminescence, coexisting with the Raman scattering, of excitonic molecules (EM) have been studied in the case of the resonant excitation. The EM's are resonantly created with wave vectors, such as k =0, k =2 k 0 and k =2.3 ∼12.2 k 0 ( k 0 =4.44 ×10 5 cm -1 ), by the two-photon excitation technique. By the use of model calculations based on the Gaussian distribution in the k-space, the EM's are inferred to re-distribute anisotropically in the range | k -2 k 0 | ≤2.5 k 0 and | k | ≤1.5 k 0 for the excitation into k =2 k 0 and k =0, respectively. EM's created at large k re-distribute isotropically, and the emitted light is shown to be due to the hot luminescence during the cooling process.