Einstein A coefficients, oscillator strengths and lifetimes for some selected triplet-triplet transitions of N2 : a comparison between theory and experiment

Abstract

Einstein A coefficients, oscillator strengths and lifetimes have been calculated by an asymptotic expansion method, introduced by Chang and Karplus, for the N2, B 3Πg→A 3Σ+u (first positive), C 3Πu→B 3Πg (second positive), W 3Δu⇄B 3Πg (Wu–Benesch) and B′ 3Σ−u→B 3Πg (infrared afterglow) band systems, using theoretical electronic transition moments, Re (r), of Yeager and McKoy. Whenever possible, comparison has been made with those calculated from the electric dipole moment functions, Re (r̄), which are functions of r̄ centroids, obtained from band intensity or lifetime measurements. Excellent agreement has been obtained in the case of the second positive band system of molecular nitrogen. However, for all other cases, conventional Re (r̄) functions are found to be superior to the theoretical Re (r) functions of Yeager and McKoy.