Experimental verification of line- and band-shape asymmetry in the Schumann–Runge system of O[sub 2]

Abstract

High-resolution, laser-based photoabsorption cross-section measurements in the weakly absorbing windows between the (11,0) and (16,0) Schumann–Runge bands of O₂ have been performed at liquid-nitrogen temperature and the results compared with corresponding coupled-channel Schrödinger-equation (CSE) and line-by-line model calculations. While the symmetric-line- shape-based line-by-line model cross sections differ significantly from experiment, the excellent agreement found between the CSE and experimental window cross sections serves to confirm clearly for the first time the CSE-model predictions of band shape asymmetry and quantum-mechanical interference effects, especially in the (11,0)–(14,0) band region.