Raman investigation of rotational and translational excitations in K1−x(NH4)xI mixed crystals

摘要: Using Raman scattering experiments we have investigated the rotational and translational modes in K1−x(NH4)xI mixed crystals for ammonium concentrations x=0.005, 0.07, 0.16, x=0.46 a fully deuterated isomorph with x(D)=0.42. The A1g+4Eg T2g responses been measured at atmospheric pressure paraelectric plastic phase (T=295 K) orientational glassy (T=7 K). In low‐frequency region ν=5–600 cm−1, seven active components could be identified. These bands are entirely due to admixture of anisotropic NH+4 pure KI. Their contributions result either from reorientations molecules between equivalent directions rotational‐like excitations around these preferential orientations, or whole Brillouin zone. this peculiar case, disorder lifts wave vector conservation processes. An interpretation different allowed transitions is proposed. composition a...