Power reflection spectroscopy near the brewster angle. Molecular dynamics of liquids

Abstract

Power reflection spectroscopy has been investigated theoretically for potential use with dipolar liquids as a means of evaluating the molecular dynamics and interactions. Calculations have been made with and without a dynamic internal field correction. This does not affect in any way the major features of the spectra in σ and π polarisation at various values of ϕ, the incident angle. Near a Brewster angle (ϕ_B= tan^–1ε^1/2_p, where ε_p is the high frequency permittivity), the reflectivity r develops a high frequency peak, typically in the mid-infrared. This brings the study of librational molecular dynamics within range of conventional spectrometers, provided that the problems of amplification and detection of the reflected r_π radiation can be overcome.