The pure rotational atmospheric lines of hydroxyl

Pure rotational line positions of the hydroxyl radical (OH) have been calculated for all vibrational levels expected in the earth's atmosphere (v = 0–9) and for lower rotational quantum numbers J″=0.5–12.5. These positions have been tabulated and compared with those derived from energy levels obtained from precise near-i.r. vibration-rotation bands and show good agreement for low J″ values. A tentative identification has been made of three v = 0 lambda-type doublets in a high-resolution far-i.r. (30–120 cm^-1) emission spectrum of the atmosphere obtained at 30 km from a balloon-borne platform. Line strength (S_J′J″) and integrated intensity (S_q cm^-2atm^-1) values have been derived for these pure rotational transitions as an aid to further work and instrument design.