Metastable dimer contributions to the collision-induced fundamental absorption spectra of N 2 and O 2 pairs

Abstract

The contributions of dimer transitions to the low-temperature collision-induced fundamental spectra of N 2 and O 2 have been observed in many earlier studies. However, recent measurements made at high resolution have shown the existence of periodic structures superposed on the smooth collision-induced envelope which persist to room temperatures. In a series of recent papers, we have compared theoretical calculations with experimental data for N 2–N 2, O 2–O 2, N 2–O 2 and O 2–N 2 pairs and have concluded that the observed structure was not due to either collisional line mixing or intercollisional interference. In the present paper, we show that one can get both qualitative and quantitative agreement between theory and experiment by including the contributions due to metastable dimers that are expected to be present at the few percent level.