Pressure-Induced Rotational Quadrupole Spectra of HCl and HBr

Abstract

Spectra of pure HCl and HCl–SF₆ mixtures were taken in the range 350 to 520 cm⁻¹, and of HBr, HBr–SF₆, HBr–CF₄ in the range 310 to 470 cm⁻¹. For the mixtures, clearly defined peaks are observed at frequencies in these regions for the ΔJ=2 selection rule of quadrupole‐induced dipole absorption, direct dipole intensities being much weaker. Calculated molecular quadrupole moments from integrated intensities are Q_HCl=5.8×10⁻²⁶ esu·cm² and Q_HBr=5.5×10⁻²⁶ esu·cm².