Revisiting the Disorder–Order Transition in 1-X-Adamantane Plastic Crystals: Rayleigh Wing, Boson Peak, and Lattice Phonons

In this paper, we revisit the disorder–order transition in 1-chloro-adamantane and present new data on 1-bromo-adamantane. Rayleigh scattering Raman-active optical lattice phonons are used to easily characterize phase change. Unlike Cl-derivative, Br-derivative shows a semiordered structure vicinity of ambient P,T conditions, which is peculiar compound seems be due more reduced rotational disorder with respect other halogen-adamantanes. The briefly discussed terms its Wing Boson peak.