IR spectroscopic study of the HCl⋯O3 molecular complex in liquid argon

Abstract

Infrared spectra are reported of ozone and HCl dissolved in liquid argon (86–134K) at concentrations varying from 5×10−5 to 9×10−6M for HCl, and from 1×10−3 to 5×10−5M for ozone. At low concentrations of O3 and of HCl, no spectral features due to O3–HCl complex were found. At higher concentrations (1×10−3 of ozone vs 5×10−5–9×10−6 of HCl), a new band near 2840cm−1 due to the HCl⋯O3 complex was observed. FWHM of νHCl of the complex is 8cm−1. From the temperature dependence of the absorption band intensity, the enthalpy of the complex formation was estimated, ΔH°=4.7±0.4kJmole−1. The optimized geometry of the cis-HCl⋯O3 complex and a value of 6.3kJmole−1 for its binding energy were determined by ab initio calculations.