Resonant Raman scattering in Ga(As, P) mediated by (localized exciton-LO phonon) complex

Abstract
Resonance light scattering experiments in polar crystals at energies corresponding to Eex + nħωLO have suggested that dressed excitons are the relevant intermediate states. Configuration coordinate model is applied to calculate the resonance Raman spectrum (intensity of phonons lines as a function of incident frequency) of the mixed crystal GaAs 0.2P0.8 and compared with experimental results of Oueslati, Hirlimann and Balkanski (J. Physique 42 (1981) 1151-1156). This analysis gives coupling constants V1 and V2 of a localized exciton with the LO1 phonon and the LO2 phonon respectively : V1/ħωLO1 = 0.7 ± 0.2; V2/ ħωLO2 = 1.4 ± 0.3, and exciton energy E0 = 2.442 eV with its width γ = 0.030 eV