Department of Physical and Organic Chemistry, Institute Jožef Stefan, Jamova c. 39, SI-1000 Ljubljana, Slovenia.
J Phys Chem A. 2011 Oct 13;115(40):11008-15. doi: 10.1021/jp204868k. Epub 2011 Sep 21.
The gas-phase reaction between HOSO and NO(2) was examined using density functional theory. Geometry optimizations and frequency computations were performed at the B3LYP/6-311++G(2df,2pd) level of theory for all minimum species and transition states. The ground-state potential energy surface, including activation energies and enthalpies, were calculated using the ab initio CBS-QB3 composite method. The results suggest that the addition of HOSO and NO(2) leads to two possible intermediates, HOS(O)NO(2) and HOS(O)ONO, without any energy barrier. The HOS(O)NO(2) easily decomposes into HONO + SO(2) through the low energy product complex HONO···SO(2), whereas the HOS(O)ONO dissociates to HOSO(2) + NO products. This latter dissociation is preferred from the isomerization of the HOS(O)ONO to HOS(NO)O(2). Also, HOS(O)NO(2) isomerization to HOS(O)ONO is hindered due to the presence of a large energy barrier. From the thermodynamic aspect, the main products in the title reaction are HONO + SO(2), whereas HOSO(2) + NO are expected as a minor products.
采用密度泛函理论研究了 HOSO 和 NO(2)之间的气相反应。在 B3LYP/6-311++G(2df,2pd)理论水平上对所有的最小物种和过渡态进行了几何优化和频率计算。使用从头算 CBS-QB3 复合方法计算了包括活化能和焓在内的基态势能面。结果表明，HOSO 和 NO(2)的加成导致了两种可能的中间体，HOS(O)NO(2)和 HOS(O)ONO，没有任何能量障碍。HOS(O)NO(2)容易通过低能产物复合物 HONO···SO(2)分解为 HONO + SO(2)，而 HOS(O)ONO 则解离为 HOSO(2) + NO 产物。从 HOS(O)ONO 异构化为 HOS(NO)O(2)的角度来看，这种后一种解离更为有利。此外，由于存在较大的能量障碍，HOS(O)NO(2)的异构化为 HOS(O)ONO 受到阻碍。从热力学角度来看，标题反应的主要产物是 HONO + SO(2)，而 HOSO(2) + NO 预计是次要产物。
