Barriers to internal rotation of CH3 groups in solid Au2I2(CH3)4 from infra-red band shape measurements

Abstract

The band shape of the asymmetric CH₃ deformation vibration in the infra-red spectrum of Au₂I₂(CH₃)₄ has been studied as a Cs I disk at temperatures from 90°K to 298°K. The barrier to internal rotation in the solid state has been calculated by two methods based on those of Bulanin and Orlova, and of Rakov. A mean value of the barrier is estimated as 270 ± 70 cm.⁻¹.