Pulsed photoacoustic spectroscopy of I

Abstract

A novel approach based on the use of λ = 532 nm pulsed radiation obtained by the second-harmonic generation from the Q-switched Nd: YAG laser and its application for excitation of acoustic modes in a specially designed multi-resonant high-Q factor photoacoustic (PA) cell is reported. The cell is employed for time-domain spectroscopic studies of gaseous NO2 and I2 molecules. The time-resolved spectra of NO2 and I 2 were recorded up to 8000 Hz and 26 000 Hz, respectively. It has been demonstrated for the first time that excited cavity modes which correspond to different transition lines of the I2 molecules show different behaviors under different pressure and input laser energy. The lowest limit of detection attained with the proposed PA system for NO2 buffered in realistic air was 14.6 ppbV. © 2012 Springer Science+Business Media New York.