Improved photoionization rates of O2(1Δ/sub g/) in the D region

The recent discovery of relatively large concentrations of O 2 ( 1 Δ g ) in the upper atmosphere had led to consideration of photoionization of this metastable molecule as a major source of O 2 + in the D region. Our initial calculations indicated that this process was less important than previously believed, primarily because of CO 2 absorption. In this paper we consider further the effect of various reasonable O 2 , CO 2 , and O 2 ( 1 Δ g ) density profiles on the ion‐production rates by this process. Within the limits described herein the ion‐production rate (ion cm −3 sec −1 ) is approximated by the following function of N o 2 , the O 2 column density in molecules per square‐centimeter column, and n 1Δ , the O 2 ( 1 Δ g density in molecules per cubic centimeter: urn:x-wiley:00486604:media:rds494:rds494-math-0001