Determining Rate Constants and Mechanisms for Sequential Reactions of Fe+ with Ozone at 500 K

详细信息    查看全文

• 作者：Joshua J. MelkoShaun G. Ard ; Trí Lê ; Gregory S. Miller ; Oscar Martinez Jr. ; Nicholas S. Shuman ; Albert A. Viggiano
• 刊名：Journal of Physical Chemistry A
• 出版年：2017
• 出版时间：January 12, 2017
• 年：2017
• 卷：121
• 期：1
• 页码：24-30
• 全文大小：347K
• ISSN：1520-5215

文摘

We present rate constants and product branching ratios for the reactions of FeO<sub>xsub><sup>+sup> (x = 0–4) with ozone at 500 K. Fe<sup>+sup> is observed to react with ozone at the collision rate to produce FeO<sup>+sup> + O<sub>2sub>. The FeO<sup>+sup> in turn reacts with ozone at the collision rate to yield both Fe<sup>+sup> and FeO<sub>2sub><sup>+sup> product channels. Ions up to FeO<sub>4sub><sup>+sup> display similar reactivity patterns. Three-body clustering reactions with O<sub>2sub> prevent us from measuring accurate rate constants at 300 K although the data do suggest that the efficiency is also high. Therefore, it is probable that little to no temperature dependence exists over this range. Implications of our measurements to the regulation of atmospheric iron and ozone are discussed. Density functional calculations on the reaction of Fe<sup>+sup> with ozone show no substantial kinetic barriers to make the FeO<sup>+sup> + O<sub>2sub> product channel, which is consistent with the reaction’s efficiency. While a pathway to make FeO<sub>2sub><sup>+sup> + O is also found to be barrierless, our experiments indicate no primary FeO<sub>2sub><sup>+sup> formation for this reaction.