Study of collision-induced oxygen complexes

Vasilchenko S.S., Serdyukov V.I., Sinitsa L.N., Voronin B.A., Polovtseva E.R.
  1. V.E. Zuev Institute of Atmospheric Optics SB RAS, Russia

   The (O2)2 molecular complexes play an important role in
   atmospheric chemistry and radiation transfer, however many properties of
   these atmospheric complexes are still far from being entirely understood.
   The authors present the results of investigation of collision-induced
   absorption of oxygen complexes (O2)2 by spectroscopic
   technique. The absorption of oxygen complexes (O2)2 were
   investigated by high resolution Fourier transform spectrometer (FTS)
   IFS-125M. The FTS is used for ground-based infrared solar absorption
   atmospheric measurements at the Zuev Institute of Atmospheric Optics SB
   RAS, Tomsk. The experimental system is equipped with a sun tracker that
   provides continuous solar tracking throughout the day.   The FTS solar 

  absorption spectra were recorded in the spectral range   of 477-1060 nm with

  spectral resolutions of 0.01, 0.1, 1.0 and 10 cm-1 under
   clear-sky conditions. High-quality long term measurements have been
   applied to determine the collision-induced absorption. The spectral data
   obtained under various experimental conditions were analyzed. It was
   revealed, that for measurements along the path close to the horizon there
   are several strong oxygen dimers absorption bands with center at 1060,
   630, 577 and 477 nm as well as O3 absorption band centered at 602
   nm that was confirmed by the experimental works. Our studies have detected
   a seasonal variability of atmospheric oxygen complex amount. In winter the
   continual absorption of O4 species reaches 10-20 percent at 630
   and 577 nm for a big solar zenith angles and 1-2 percent in summer for a
   small solar zenith angles. It is shown that oxygen dimers continual
   absorption at 577 nm might be up to 10 percent for slant optical path of
   15 km, atmospheric pressure of 760 Torr, and room temperature. It is
   necessary to take into account oxygen dimers absorption to estimate
   realistic atmospheric concentration of O3. Error in measurement of
   atmospheric ozone concentration can reach 20 percent not considering the
   (O2)2 molecular complexes contribution to the observed
   absorption.

  

   The work is partly supported by the Russian Fund for Basic Research
   Grants, RAS Program 3.9.