A. Amoruso et al., NEW MEASUREMENTS OF THE NO2 ABSORPTION CROSS-SECTION IN THE 440-NM TO460-NM REGION AND ESTIMATES OF THE NO2-N2O4 EQUILIBRIUM-CONSTANT, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 98(D9), 1993, pp. 16857-16863
Absolute determinations of the NO2 absorption cross section in the 440
- to 460-nm region at different temperatures are reported. This region
is of special interest for remote sensing applications. The interpret
ation of the results is rendered complex by the coexistence of NO2 and
its dimer. In the experiment both NO2 and N2O4 absorption features ar
e observed. Different approaches are utilized to obtain the partial pr
essure of NO2; a new estimate of the NO2-N2O4 equilibrium constant fro
m spectroscopic measurements is also obtained. Within experimental err
ors the overall shape of the spectrum does not show a dependence on te
mperature, but some features are affected; in particular, a slight inc
rease of a few maxima and a decrease of the other maxima and of the mi
nima when the temperature is lowered have been observed.