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 QHCl=5.8×10−26 esu·cm2 and QHBr=5.5×10−26 esu·cm2.