• rovibronic bands;
  • red atmospheric band;
  • infrared atmospheric band;
  • spin-orbit coupling;
  • quadratic response


Intensity distribution in rotational lines of the 0–0 band of the a1Δg [RIGHTWARDS ARROW] X3Σmath image transition in the oxygen molecule at λ = 1270 nm is studied by quadratic response (QR) method in a framework of multiconfiguration self-consisted field (MCSCF) theory. The distance dependence of the transition magnetic moment and the (0–0)/(0–1) bands intensity ratio are calculated. A short review of previous theory of the red and infrared atmospheric oxygen bands and of their enhancement by collisions is presented to analyze and compare the new results. Enhancement of these bands in O2 collisions with Li2 and N2 molecules is calculated by QR method. Diamagnetic species simulate solvent molecules of different optical polarizability. Specific influence of collisions on vibronic bands is stressed. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009