Accurate measurements of collision-induced absorption by pure nitrogen in the fundamental band near 4.3 μm have been made in the 0–10 atm and 230–300 K pressure and temperature ranges, respectively. A Fourier-transform spectrometer was used with a resolution of 0.5 cm−1. The current measurements, which agree well with previous ones but are more precise, reveal that weak features are superimposed on the broad N2 continuum. These features have negligible temperature dependence, and their origin is not clear at the present time. Available experimental data in the 190–300 K temperature range have been used to build a simple empirical model that is suitable for use to compute atmospheric N2 absorption. Tests indicate that this model is accurate unlike the estimates produced by widely used atmospheric transmission codes.
© 1996 Optical Society of America
Original Manuscript: January 11, 1996
Revised Manuscript: April 17, 1996
Published: October 20, 1996
Walter J. Lafferty, Alexander M. Solodov, Alfons Weber, Wm. Bruce Olson, and Jean-Michel Hartmann, "Infrared collision-induced absorption by N2 near 4.3 μm for atmospheric applications: measurements and empirical modeling," Appl. Opt. 35, 5911-5917 (1996)