Absolute cross sections of ozone at atmospheric temperatures for the Wulf and the Chappuis bands.

Ozone absorption constitutes a variable background against which measurement of pollution is observed from satellites by the solar occultation technique. The temperature-altitude gradient of ozone spans the range 180-340 K. Laboratory measurements of ozone absorption at temperatures across this range are needed to calibrate spectroscopic remote sensing, but have yielded results in substantial disagreement with each other.

Contribution to the analysis of the predissociated rovibronic structure of the symmetric isotopomers 16O3 and 18O3 of ozone near 10,400 cm-1): [3A2(3(2)(0)) <-- X1A1(0(0)(0))] and 3B2 <-- X1A1.

The absorption spectrum of ozone was recorded at low temperatures (down to -135 degrees C) by high resolution Fourier transform spectrometry and intra cavity laser absorption spectroscopy (ICLAS) near 10,400 cm-1. A preliminary analysis of the rotational structure of the absorption spectra of 16O3 and 18O3 shows that this spectral region corresponds to a superposition of two different electronic transitions, one with a very broad rotational structure, showing for the first time the asymmetric stretching frequency mode nu3 of the electronic state 3A2, the other formed by a completely diffuse band, probably the 2(1)(0) band of a new transition due to the triplet electronic state 3B2. Predissociation effects induce large broadening of the rotational lines for the transition centered at 10,473 cm-1 identified as the 3(2)(0) band of the 3A2 <-- X1A1 electronic transition.

Spectroscopy and predissociation of the 3A2 electronic state of ozone 16O3 and 18O3 by high resolution Fourier transform spectrometry.

A high resolution Fourier transform spectrometry analysis of the rotational structure of the 2(0)1 absorption bands of the 3A2<--X1A1 Wulf transition for the isotopomers 16O3 and 18O3 of the ozone molecule is presented. These bands are very intense compared to the 0(0)0 bands but the predissociation is so strong that the main sub-bands appear as continuous contours. Isolated lines and band contour methods are used together to analyse these two rovibrational bands.

Contribution to the Analysis of the 3A2 <-- &Xtilde;1A1 "Wulf" Transition of Ozone by High-Resolution Fourier Transform Spectrometry.

The analysis of the rotational structure of the high-resolution Fourier transform 0(0)0 absorption spectrum of the 3A2 <-- &Xtilde;1A1 band system of the "Wulf" transition of the isotopomer 16O3 of ozone is reported for the first time. With a near pure case (b) coupling model for the upper triplet state, we have assigned a significant portion of the spectrum, mainly the F1 (J = N + 1) and F2 (J = N) spin components, primarily in the lower frequency region of the band. The lines corresponding to the F3 (J = N - 1) component are weak at lower frequencies and heavily congested in the central and higher frequency regions of the spectrum.

Fourier-transform lidar.

We propose a new method based on the differential absorption lidar technique for multipollutant detection. A broadband laser is sent into the atmosphere in a wavelength range in which several pollutants absorb. The backscattered light is analyzed by a Fourier-transform spectrometer with time resolution.