Absorption Intensities of the Lattice Modes of Crystalline HCl and HBr

Abstract

The absolute absorption intensities of the infrared active lattice modes of crystalline HCl and HBr have been measured. Assignments based on the experimental intensities indicate that all of the fundamental lattice modes lie below 350 cm⁻¹. A dipolar coupling model was used to calculate the expected intensities. A comparison of observed intensities with calculated intensities gives evidence that the molecular dipole moments of crystalline HCl and HBr are less than their gas‐phase values.