Kinetics of Sulfur Oxide, Sulfur Fluoride, and Sulfur Oxyfluoride Anions with Ozone |
| |
Authors: | AA Viggiano Susan T Arnold Skip Williams Thomas M Miller |
| |
Institution: | (1) Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Massachusetts, 01731-3010 |
| |
Abstract: | Rate constants and product branching ratios were measured for eleven sulfur oxide, sulfur fluoride, and sulfur oxyfluoride anions reacting with O3. The SO–
2 ion reacts rapidly to form –O–
3, SO–
3, and e–. The temperature dependence of the branching ratio shows more reactive detachment and less SO–
3 formation at higher temperature. SO–
3 reacts with O3, forming SO–
4 at 1/3 to 1/4 of the collisional rate from 200 to 500 K, respectively. At 300 K, SF–
6 charge transfers to O3 at 20% of the collisional rate. F2SO–
2 reacts with O3 at a few percent of the collision rate, forming both O–
3 and FSO–
3; The ion F3SO– reacts slowly with O3 to form F3SO–
2. The ions SO–
4, SF–
5, FSO–
2, FSO–
3, F3SO–, and F5SO– are unreactive with O3. A trend is noted relating the ion reactivity with the coordination of the central sulfur atom, i.e., the number of S–F bonds plus two times the number of S=O bonds. Only ions with a sulfur coordination of 4 or 6 are reactive, although the reaction rate constants are generally small. The reactivity trends appear to be partially explained by spin conservation. These reactions are all sufficiently slow, so O3 reactions should not play a major role in SF6/O2 discharges. All ions studied have been found to be unreactive with O2. |
| |
Keywords: | Electron impact ion source kinetics of sulfur compounds role of ozone negative ion plasma density |
本文献已被 SpringerLink 等数据库收录! |
|