Temperature Dependences for the Reactions of O(-) and O(2-) with O(2)(a1-delta-g) from 200 to 700 K
Abstract
Rate constants and product ion distributions for the O" and O(2) reactions with 02(a delta g) were measured as a function of temperature from 200 to 700 K. The measurements were made in a selected ion flow tube (SIFT) using a newly calibrated 0:(a'As) emission detection scheme with a chemical singlet oxygen generator. The rate constant for the 02" reaction is ~7 x 10(-10) cm(3) s(-1) at all temperatures, approaching the Langevin collision rate constant. Electron detachment was the only product observed with 02" The O- reaction shows a positive temperature dependence in the rate constant from 200 to 700 K. The product branching ratios show that almost all of the products at 200 K are electron detachment, with an increasing contribution from the slightly endothermic charge-transfer channel up to 700 K, accounting for 75% of the products at that temperature The increase in the overall rate constant can be attributed to this increase in the contribution of the endothermic channel. The charge-transfer product channel rate constant follows the Arrhenius form, and the detachment product channel rate constant is essentially independent of temperature with a value of approx. 6.1 x 10(-11) cm(3) s(-1).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 2008
- Accession Number
- ADA494150
Entities
People
- Albert A Viggiano
- Anthony Midey
- Itzhak Dotan
Organizations
- Air Force Research Laboratory