Diode laser based detection and determination of pressure-induced broadening coefficients in the ν1+ν3 combination band of ammonia
Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
Corresponding author: a email@example.com
Revised: 13 August 2003
Published online: 21 October 2003
Nitrogen, oxygen, air and self-broadening coefficients have been measured in direct absorption for six transitions in the ν1+ν3 combination band of ammonia at room temperature using a DFB diode laser operating at 1.51 μm. Absorption cross-sections for these strong lines, suitable for detection purposes, have been determined. Using 2f wavelength modulation spectroscopy we demonstrate a minimum detectable concentration of 500 ppb in a 75 cm path in 1 s at atmospheric pressure and present a simple method for measurement of broadening coefficients.
PACS: 33.20.Ea – Infrared spectra / 33.20.Vq – Vibration-rotation analysis / 33.70.Jg – Line and band widths, shapes, and shifts
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004