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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Ab initio study on mechanisms and kinetics for reaction of NCS with NO
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Ab initio study on mechanisms and kinetics for reaction of NCS with NO

机译：从头开始研究NCS与NO反应的机理和动力学

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The mechanisms and kinetics of the reaction of a thiocyanato radical (NCS) with NO were investigated by a high-level ab initio molecular orbital method in conjunction with variational RRKM calculations. The species involved were optimized at the B3LYP/6-311 ++G(3df,2p) level, and their single-point energies were refined by the CCSD(T)/aug-cc-PVQZ//B3LYP/6-311+G(3df,2p) method. Our calculated results indicate favorable pathways for the formation of several isomers of an NCSNO complex. Formation of OCS + N-2 also is possible, although this pathway involves a substantial energy barrier. The predicted total rate constants, k(total) at a 2 torr He pressure can be represented by the following equations: k(total) = 9.74 x 10(26)T(-13.88) exp(-6.53 (kcal mol(-1))/RT) at T = 298-950 K and 1.17 x 10(-22)T(2.52) exp(-6.86 (kcal mol(-1))/RT) at T = 960-3000 K, in units of cm(3) molecule(-1) s(-1), and the predicted values are in good agreement with the experimental results in the temperature range of 298-468 K. The calculated results clearly indicate that the branching ratio for R-M1 in the temperature range of 298-950 K has the largest value (R-M1, accounts for 0.53-0.39). However, in the higher temperature range (960-3000 K), the formation of OCS + N-2 (P5) with branching ratio R-P5 (0.40-0.79) becomes dominant. The rate constants for key individual product channels are provided for different temperature and pressure conditions.
机译：通过高级从头算分子轨道方法结合变分RRKM计算，研究了硫氰酸根自由基（NCS）与NO反应的机理和动力学。在B3LYP / 6-311 ++ G（3df，2p）水平上优化了所涉及的物种，并通过CCSD（T）/ aug-cc-PVQZ // B3LYP / 6-311 +优化了它们的单点能量。 G（3df，2p）方法。我们的计算结果表明了形成NCSNO配合物的几种异构体的有利途径。 OCS + N-2的形成也是可能的，尽管该途径涉及大量的能量屏障。在2 torr He压力下的预测总速率常数k（total）可用以下公式表示：k（total）= 9.74 x 10（26）T（-13.88）exp（-6.53（kcal mol（-1 ））/ RT）在T = 298-950 K和1.17 x 10（-22）T（2.52）exp（-6.86（kcal mol（-1））/ RT）在T = 960-3000 K时，单位为cm（3）分子（-1）s（-1），其预测值与在298-468 K的温度范围内的实验结果非常吻合。计算结果清楚地表明R-M1的支化比在298-950 K的温度范围内具有最大值（R-M1，占0.53-0.39）。但是，在较高的温度范围（960-3000 K）中，支化比R-P5（0.40-0.79）的OCS + N-2（P5）的形成变得占主导地位。提供了针对不同温度和压力条件的关键单个产品通道的速率常数。

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