Eur. Phys. J. D 42, 41-47 (2007)
https://doi.org/10.1140/epjd/e2006-00275-y

High resolution polarization spectroscopy and laser induced fluorescence of CO₂ around 2μm

¹ School of Chemical Engineering, University of Adelaide, Adelaide, SA, 5005, Australia
² Division of Combustion Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden

Corresponding author: ^a zeyad.alwahabi@adelaide.edu.au

Received: 19 September 2006
Revised: 21 November 2006
Published online: 22 December 2006

Abstract

High resolution Infrared Polarisation Spectroscopy (IRPS) and Infrared Laser Induced Fluorescence (IRLIF) techniques were used to probe CO₂/N₂ binary gas mixture at atmospheric pressure and ambient temperature. The probed CO₂ molecules were prepared by laser excitation to an overtone and combination ro-vibrational state (12⁰1, J=15) of CO₂, centred at 4988.6612 cm^-1. IRPS and IRLIF line profiles were recorded for several CO₂/N₂ binary mixtures. The observed IRLIF line shapes have the expected Lorentzian form while the observed IRPS line shapes are narrower by a factor of two than those recorded with the IRLIF and appear to have a Lorentzian-cubed profile. The recorded line profiles provide measurements of the pressure-broadening coefficient directly at atmospheric pressure. The Full-Width-Half-Maxima (FWHM) pressure broadening coefficients are measured, based on IRLIF, to be 0.2174±0.0092 cm^-1atm^-1 and 0.1327 ±0.0077 cm^-1atm^-1 for self- and N₂ collision broadening, respectively. The broadening coefficients obtained based on IRPS were measured to be ~8% larger than those obtained with IRLIF.