The photochemistry of ozone at 193 and 222 nm

Abstract

The quantum yields for the formation of O(1 D) and O(3 P) from the photolysis of ozone have been measured at 222 and 193 nm. The quantum yield for O(3 P) was observed to be Φ(3 P)=0.13±0.02 at 222 nm, and the primary quantum yield for O(1 D) was found to be Φ(1 D)=0.87±0.04. This measurement is consistent with other studies of O3photolysis within the Hartley band which indicate that a significant portion (5–15%) of the products are formed in the ground state. At 193 nm the quantum yield for the production of excited state O(1 D) atoms is Φ(1 D)=0.46±0.29, which is significantly less than what is observed during photolysis within the lower energy Hartley band. The quantum yield for O(3 P) atoms at 193 nm was found to be 0.57±0.14. We have also observed that the quantum yield for O atoms [O(1 D)+O(3 P)] is greater than unity [Φ(O)=1.20±0.15] at 193 nm indicating the presence of a channel which produces three O(3 P) atoms. O2(b 1Σ) has also been detected and quantified, Φ(b 1Σ)=0.50±0.38, from O3photolysis at 193 nm. These measurements suggest that O(1 D) and O2(b 1Σ) are co‐produced.