BROADENING PARAMETERS OF NO2 LINES IN THE 3.4 MU-M SPECTRAL REGION

Fourier transform spectra have been recorded to measure self-, N-2-, a nd O-2-broadening coefficients of NO2 lines in the upsilon(1) + upsilo n(3) band. For the studied set of transitions, a slight rotational dep endence of the broadening coefficients exists versus N '', the rotatio nal quantum number of the lower level of the transition, whereas no si gnificant dependence is observed versus K-a ''. An empirical relation, allowing one to calculate approximate values of the air-broadening co efficients gamma(air)(0), at 296 K, for lines observable in atmospheri c spectra recorded from the ground, is proposed: gamma(air)(0) = 84.1 - 0.753 N '' + 0.0059 N ''(2), in 10(-3) cm(-1). atm(-1), with an unce rtainty of about +/- 10% when N '' and K-a '' are smaller than about 4 0 and 10, respectively. For typical lines used for atmospheric applica tions, the single value reported in the HITRAN database for all lines of all bands of NO2 can differ by more than 20% from the measured ones . (C) 1997 Elsevier Science Ltd.