This study undertakes a detailed theoretical investigation into the iso-pentanol radical isomerization and decomposition kinetics and the mechanism development of the iso-pentanol oxidation. The CCSD(T)/CBS//M08-HX/6-311+G(2df,2p) method was adopted to calculate the reaction potential energy surface. The reaction rate coefficients were calculated by variational transition state theory (VTST) with multistructural torsional (MS-T) partition function and small curvature tunneling (SCT) correction. Moreover, the pressure-dependent rate coefficients were determined using the system-specific quantum Rice-Ramsperger-Kassel theory (SS-QRRK). The variational and tunneling effects were discussed, and the dominant reaction channels were identified. It reveals that the isomerization reactions play a significant role at low temperatures, while the decomposition reactions dominate the high-temperature regime. Notably, the quantitative rate expressions for iso-pentanol radical decomposition reactions were also obtained. Furthermore, a new kinetic model incorporating the calculated rate coefficients was constructed, exhibiting satisfactory prediction performance on ignition delay times and improved predictive accuracy of species mole fractions. This work provides accurate rate data of isomerization and decomposition kinetics and contributes to a more comprehensive understanding of the iso-pentanol oxidation mechanism.

中文翻译：

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异戊醇氧化化学理论研究：燃料自由基异构化分解动力学及机理研究

本研究对异戊醇自由基异构化和分解动力学以及异戊醇氧化的机理发展进行了详细的理论研究。采用CCSD(T)/CBS//M08-HX/6-311+G(2df,2p)方法计算反应势能面。反应速率系数通过变分过渡态理论（VTST）与多结构扭转（MS-T）配分函数和小曲率隧道（SCT）校正计算。此外，压力相关的速率系数是使用系统特定的量子 Rice-Ramsperger-Kassel 理论 (SS-QRRK) 确定的。讨论了变分效应和隧道效应，并确定了主要反应通道。它表明异构化反应在低温下发挥重要作用，而分解反应在高温状态下占主导地位。值得注意的是，还获得了异戊醇自由基分解反应的定量速率表达式。此外，构建了结合计算的速率系数的新动力学模型，在点火延迟时间方面表现出令人满意的预测性能，并提高了物质摩尔分数的预测精度。这项工作提供了异构化和分解动力学的准确速率数据，有助于更全面地了解异戊醇氧化机理。