FTIR-based measurements of self-broadening and self-shift coefficients as well as line strength in the first overtone band of HCl at 1.76 µM

Abstract

FTIR spectra of the 2-0 band of HCl have been measured in the 5300-5900 cm^-1 spectral region at 15 different pressures (0.05-2.5 bar) and at a spectral resolution of 0.07 cm^-1. For the first time, reliable and consistent self-induced broadening and shift coefficients for the complete HCl 2-0 band have been reported. Line intensities determined from a robust regression analysis with improved uncertainties are also presented. Compared to previous laser-based measurement for the R3 line {Ortwein et al., Appl Phys B: Lasers Opt 2010;100:341-7}, our newly measured γ_self coefficient and line intensity are 1.35% and 0.10% larger, respectively. Hartmann and Boulet {Hartmann & Boulet, JCP 113, 9000 (2000)} developed a formalism describing the relation between the shift coefficients of different vibrational bands and successfully applied to Ar-HF system. Our newly measured self-induced shift coefficients suggest that the H-B formalism is not suitable for describing the HCl-HCl collisional system.