Reactions of CO2+ with H, H2 and deuterated analogues
Reactions of CO2+ with H, H2 and deuterated analogues
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DOI：
10.1016/j.ijms.2008.09.004
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发表时间：
2009-02-01
影响因子：
1.8
通讯作者：
Gerlich, D.
中科院分区：
文献类型：
--
作者：
Borodi, G.;Luca, A.;Gerlich, D.
本文用变温22极离子阱和冷中性束相结合的方法，测量了CO2+离子与H、H2-和氘代类似物反应的速率系数k（T）。中性束在冷却器中冷却到T-ACC，以良好表征的速度分布穿透被捕获的离子云。离子T-22 PT的温度已被设置为15至300 K之间的值。通过使用氦缓冲气体加速热化。作为参考，已经用热靶气体进行了一些实验。为此目的，氢气直接泄漏到阱周围的盒子中。虽然CO2+与H-2的碰撞只产生质子化产物HCO 2+，但与H原子的碰撞主要形成HCO+。未检测到电子传递通道H+ + CO2（< 20%）。对氘进行了等效研究。与原子反应的速率系数相当小。在我们小于15%的相对误差内，它们不依赖于CO2+离子的温度，也不依赖于原子的速度（k（T）在4.5和4.7 x 10（-10）cm（3）s（-1）之间，H作为目标，和2.2 x 10（-10）cm（3）s（-1）与D）。对于与分子的碰撞，反应性随着温度的降低而显著增加，在15 K时达到朗之万值。这些结果报告为k = alpha（T/300 K）（beta），其中H-2的alpha = 9.5 x 10（-11）cm（3）s（-1）和beta = -0.15，D-2的alpha = 4.9 x 10（-10）cm（3）s（-1）和beta = -0.30。(C)2008 Elsevier B. V.保留所有权利。
Combining a temperature variable 22-pole ion trap with a cold effusive beam of neutrals, rate coefficients k(T) have been measured for reactions of CO2+ ions with H, H-2 and deuterated analogues. The neutral beam which is cooled in an accommodator to T-ACC, penetrates the trapped ion cloud with a well-characterized velocity distribution. The temperature of the ions, T-22PT, has been set to values between 15 and 300 K. Thermalization is accelerated by using helium buffer gas. For reference, some experiments have been performed with thermal target gas. For this purpose hydrogen is leaked directly into the box surrounding the trap. While collisions of CO2+ with H-2 lead exclusively to the protonated product HCO2+, collisions with H atoms form mainly HCO+. The electron transfer channel H+ + CO2 could not be detected (< 20%). Equivalent Studies have been performed for deuterium. The rate coefficients for reactions with atoms are rather small. Within our relative errors of less than 15%, they do not depend on the temperature of the CO2+ ions nor on the velocity of the atoms (k(T) lays between 4.5 and 4.7 x 10(-10) cm(3) s(-1) with H as target, and 2.2 x 10(-10) cm(3) s(-1) with D). For collisions with molecules, the reactivity increases significantly with falling temperature, reaching the Langevin values at 15 K. These results are reported as k = alpha (T/300 K)(beta) with alpha = 9.5 x 10(-11) cm(3) s(-1) and beta = -0.15 for H-2 and alpha = 4.9 x 10(-10) cm(3) s(-1) and beta = -0.30 for D-2. (C) 2008 Elsevier B.V. All rights reserved.