On the temperature dependence of the integrated intensity of the collision-induced fundamental band of O₂–O₂

Abstract

The temperature dependence of the integrated intensity of the collision-induced fundamental band of O₂–O₂ pairs has been investigated. For T < 280 K, most of the intensity has been shown to arise through the long-range isotropic quadrupolar mechanism, which leads to a monotonic decrease with increasing T. Recent observations carried out at higher temperature show a small increase in the integrated intensity as T increases. Assuming that this increase in absorption is due to a short-range isotropic overlap dipole and fitting the theoretically calculated results to the experimental data, reasonable values are obtained for the magnitude and range of this dipole. The assumption is tested by calculating the corresponding spectral profiles, and it is found that these are in good agreement with the experimental measurements over the temperature range 190 K to 350 K.

Acknowledgements

The authors wish to thank Dr W. J. Lafferty for providing the experimental data for the spectral profiles. Two of authors (Q. Ma and R. H. Tipping) acknowledge financial support from NASA under grants NAG5-13337, NNG06GB23G, and FCCS-547. Q. Ma wishes to acknowledge financial support from the Biological and Environmental Research Program (BER), US Department of Energy, Interagency Agreement No. DE-AI02-93ER61744.