Armenta Butt Sam, Price Stephen D
Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
Phys Chem Chem Phys. 2021 May 19;23(19):11287-11299. doi: 10.1039/d1cp00918d.
Collisions between Ar2+ and N2 have been studied using a coincidence technique at a centre-of-mass (CM) collision energy of 5.1 eV. Four reaction channels generating pairs of monocations are observed: Ar+ + N2+, Ar+ + N+, ArN+ + N+ and N+ + N+. The formation of Ar+ + N2+ is the most intense channel, displaying forward scattering but with a marked tail to higher scattering angles. This scattering, and other dynamics data, is indicative of direct electron transfer competing with a 'sticky' collision between the Ar2+ and N2 reactants. Here Ar+ is generated in its ground (2P) state and N2+ is primarily in the low vibrational levels of the C2Σu+ state. A minor channel involving the initial population of higher energy N2+ states, lying above the dissociation asymptote to N+ + N, which fluoresce to stable states of N2+ is also identified. The formation of Ar+ + N+ by dissociative single electron transfer again reveals the involvement of two different pathways for the initial electron transfer (direct or complexation). This reaction pathway predominantly involves excited states of Ar2+ (1D and 1S) populating N2+* in its dissociative C2Σu+, 22Πg and D2Πg states. Formation of ArN+ + N+ proceeds via a direct mechanism. The ArN+ is formed, with significant vibrational excitation, in its ground (X3Σ-) state. Formation of N+ + N+ is also observed as a consequence of double electron transfer forming N22+. The exoergicity of the subsequent N22+ dissociation reveals the population of the A1Πu and D3Πg dication states.
利用符合技术在质心（CM）碰撞能量为5.1电子伏特的条件下研究了Ar2+与N2之间的碰撞。观察到四个产生单离子对的反应通道：Ar+ + N2+、Ar+ + N+、ArN+ + N+和N+ + N+。Ar+ + N2+的形成是最强烈的通道，呈现前向散射，但在较高散射角处有明显的拖尾。这种散射以及其他动力学数据表明，直接电子转移与Ar2+和N2反应物之间的“粘性”碰撞相互竞争。此处，Ar+以其基态（2P）生成，N2+主要处于C2Σu+态的低振动能级。还识别出一个次要通道，该通道涉及高于N+ + N解离渐近线的较高能量N2+态的初始布居，这些态会荧光到N2+的稳定态。通过解离性单电子转移形成Ar+ + N+再次揭示了初始电子转移存在两种不同途径（直接或络合）。该反应途径主要涉及Ar2+的激发态（1D和1S）使处于解离性C2Σu+、22Πg和D2Πg态的N2+*布居。ArN+ + N+的形成通过直接机制进行。ArN+以其基态（X3Σ-）形成，并伴有显著的振动激发。由于双电子转移形成N22+，也观察到了N+ + N+的形成。随后N22+解离的放能性揭示了A1Πu和D3Πg双离子态的布居情况。
