Absolute state-selected total cross sections for the ion{endash}molecule reactions O{sup +}({sup 4}S,{sup 2}D,{sup 2}P)+H{sub 2}(D{sub 2})
- Ames Laboratory, United States Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)
Absolute total cross sections for the state-selected reactions of O{sup +}({sup 4}S,{sup 2}D,{sup 2}P)+H{sub 2} (D{sub 2}) have been measured in the center-of-mass collision energy (E{sub c.m.}) range of 0.02{endash}12 eV. The cross sections for OH{sup +} (OD{sup +}) from O{sup +}({sup 2}D)+H{sub 2} (D{sub 2}) are slightly higher than those from O{sup +}({sup 4}S)+H{sub 2} (D{sub 2}), whereas the OH{sup +} (OD{sup +}) cross sections from O{sup +} ({sup 2}P)+H{sub 2} (D{sub 2}) are {approx}40{percent} lower than those from O{sup +}({sup 4}S)+H{sub 2} (D{sub 2}) and O{sup +} ({sup 2}D)+H{sub 2} (D{sub 2}). At E{sub c.m.}{lt}0.5 eV, the total cross sections for OH{sup +} (OD{sup +}) from O{sup +} ({sup 4}S)+H{sub 2} (D{sub 2}) and O{sup +}({sup 2}D)+H{sub 2} (D{sub 2}) are in accord with those predicted by the Langevin{endash}Gioumousis{endash}Stevenson model. Significantly higher cross sections are observed for H{sup +} (D{sup +}) and H{sub 2}{sup +} (D{sub 2}{sup +}) from O{sup +}({sup 2}D)+H{sub 2} (D{sub 2}) and O{sup +}({sup 2}P)+H{sub 2} (D{sub 2}), as compared to those from O{sup +}({sup 4}S)+H{sub 2} (D{sub 2}). The exothermic nature of the O{sup +}({sup 2}D,{sup 2}P)+H{sub 2} (D{sub 2}) charge transfer collisions accounts for the high cross sections observed for H{sub 2}{sup +} (D{sub 2}{sup +}). While the H{sup +} (D{sup +}) ions observed in the O{sup +}({sup 4}S)+H{sub 2} (D{sub 2}) reaction are identified with the H{sup +} (D{sup +})+O+H channel, the H{sup +} (D{sup +}) ions from the reactions involving O{sup +}({sup 2}D) and O{sup +}({sup 2}P) are associated mostly with the H{sup +} (D{sup +})+OH (OD) channel, the formation of which obeys the spin-conservation rule. (Abstract Truncated)
- OSTI ID:
- 435124
- Journal Information:
- Journal of Chemical Physics, Vol. 106, Issue 2; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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