Eur. Phys. J. D 28, 59-66 (2004)
https://doi.org/10.1140/epjd/e2003-00289-y

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 gus.hancock@chemistry.ox.ac.uk

Received: 14 March 2003
Revised: 13 August 2003
Published online: 21 October 2003

Abstract

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.