Department of Physics, AlbaNova, Stockholm University, SE-10691 Stockholm, Sweden.
Phys Chem Chem Phys. 2010 Oct 7;12(37):11670-3. doi: 10.1039/c003857a. Epub 2010 Aug 11.
The dissociative recombination of the acetaldehyde cation, CH(3)CHO(+), has been investigated at the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory in Stockholm, Sweden. The dependence of the absolute cross section of the reaction on the relative kinetic energy has been determined and a thermal rate coefficient of k(T) = (1.5 ± 0.2) × 10(-6) (T/300)(-0.70±0.02) cm(3) s(-1) has been deduced, which is valid for electron temperatures between ∼10 and 1000 K. The branching fractions of the reaction were studied at ∼0 eV relative kinetic energy and we found that breaking one of the bonds between two of the heavy atoms occurs in 72 ± 2% of the reactions. In the remaining events the three heavy atoms stay in the same product fragment. While the branching fractions are fairly similar to the results from an earlier investigation into the dissociative recombination of the fully deuterated acetaldehyde cation, CD(3)CDO(+), the thermal rate coefficient is somewhat larger for CH(3)CHO(+). Astrochemical implications of the results are discussed.
在瑞典斯德哥尔摩的曼尼·西格班实验室的重离子储存环 CRYRING 上，研究了乙醛阳离子 CH(3)CHO(+)的离解复合反应。确定了反应的绝对截面随相对动能的依赖关系，并推导出热速率系数 k(T)=(1.5±0.2)×10(-6)(T/300)(-0.70±0.02)cm(3)s(-1)，该系数在 ∼10 到 1000 K 的电子温度范围内有效。在 ∼0 eV 的相对动能下研究了反应的分支分数，我们发现，在 72±2%的反应中，两个重原子之间的一个键断裂。在其余的反应中，三个重原子留在相同的产物碎片中。虽然分支分数与早期对完全氘代乙醛阳离子 CD(3)CDO(+)的离解复合反应的研究结果相当相似，但 CH(3)CHO(+)的热速率系数略大。讨论了这些结果的天体化学意义。
