Observation of high‐N hydroxyl pure rotation lines in atmospheric emission spectra by the CIRRIS 1A Space Shuttle Experiment

Abstract

Pure rotation line emissions from highly rotationally excited OH have been observed between 80 and 110 km tangent height under both nighttime and daytime quiescent conditions. Data were obtained using the cryogenic CIRRIS 1A interferometer, operated on the Space Shuttle. Transitions from OH(v=0–2, N′≤33) were identified between 400 and 1000 cm−1, corresponding to states with energies as high as 23000 cm−1. These are the first definitive observations of OH pure rotation transitions in the air glow, and by far the highest N levels observed in any type of OH airglow emission spectrum. The present observations of highly excited rotational states of OH parallel those made during recent field studies of NO and laboratory studies of OH, NO, and CO.

Competitive partitioning of rotational energy in gas ensemble equilibration

“…3,4 The highly inverted rovibrational populations obtained by Pimentel et al 16 for HF and by Robinson and co-workers 17 in the case of OH are readily reproduced by our model and shown to be the result of QVRT. 3 In addition, our model of OH* in N 2 /O 2 was able to reproduce the exceptionally high rotational excitation, n OH > 30, previously identified in Earth's airglow 18 as originating from OH molecules in the mesosphere. Once again, the critical mechanism is that of QVRT.…”

Development of Atmospheric Infrared Emission Models

“…In contrast with the SHARC-2 prediction, the CIRRIS-1A data near the mesopause show little obvious structure associated with the 0 3 hot bands. Fine structure previously seen in SPIRIT-1 58 has been recently shown 57 to be due instead to the OH lines. The lack of 0 3 hot band structure indicates that there are many more 0 3 bands contributing to this spectral region than are present in SHARC-2.…”

From Ligand Field Theory to Molecular Collision Dynamics: A Common Thread of Angular Momentum

“…The ensemble in our calculations represents a thermodynamically closed system from which energy and matter cannot migrate. This is not the case in Earth's atmosphere where airglow emission from n OH > 30 has been found and thought to originate from the exothermic H + O 3 reaction in the mesosphere [58] through the mechanism of QVRT. High n OH molecules are calculated to survive more collisions in air as temperature is lowered.…”

“…It is also thought to explain the remarkable persistence and exceptionally high rotational energy (n 32) of OH emission in Earth's airglow which has been detected some 12 h after sunset and therefore cannot be the result of direct solar excitation [58]. In the final part of this contribution, the AM method is used to demonstrate how such effects might come about in a multicollision environment that represents a rudimentary model of Earth's atmosphere.…”