Rate coefficients and kinetic isotope effects of the X + CH[subscript 4] → CH[subscript 3] + HX (X = H, D, Mu) reactions from ring polymer molecular dynamics
Rate coefficients and kinetic isotope effects of the X + CH[subscript 4] → CH[subscript 3] + HX (X = H, D, Mu) reactions from ring polymer molecular dynamics
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发表时间：
2013-03
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通讯作者：
Yongle Li;Y. V. Suleimanov;Jun Li;W. Green;Hua Guo
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作者：
Yongle Li;Y. V. Suleimanov;Jun Li;W. Green;Hua Guo
麻省理工学院已公开发表了这篇文章。请分享这种访问如何使您受益。你的故事很重要。摘要利用环状聚合物分子动力学（RPMD）计算了甲烷与几种氢同位素（H、D和Mu）反应的热速率系数和动力学同位素效应。与理论的H + CH 4反应的速率系数之前从多组态含时Hartree（MCTDH）计算在相同的势能面上的良好的协议提供了强有力的证据的准确性的RPMD方法。这些量子力学速率系数也是在良好的协议与先前获得的结果使用过渡态理论与半经典隧道效应的H/D + CH 4反应。然而，它示出的RPMD速率系数的超轻Mu反应与CH 4是显着小于实验数据，推测表明在势能面的不准确性。RPMD和过渡态理论的结果之间的显着差异也被发现这个具有挑战性的系统。
The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract The thermal rate coefficients and kinetic isotope effects have been calculated using ring polymer molecular dynamics (RPMD) for the prototypical reactions between methane and several hydrogen isotopes (H, D, and Mu). The excellent agreement with the theoretical rate coefficients of the H + CH 4 reaction obtained previously from a multi-configuration time-dependent Hartree (MCTDH) calculation on the same potential energy surface provides strong evidence for the accuracy of the RPMD approach. These quantum mechanical rate coefficients are also in good agreement with the results obtained previously using the transition-state theory with semi-classical tunneling corrections for the H/D + CH 4 reaction reactions. However, it is shown that the RPMD rate coefficients for the ultralight Mu reaction with CH 4 are significantly smaller than the experimental data, presumably suggesting inaccuracies in the potential energy surface. Significant discrepancies between the RPMD and transition-state theory results have also been found for this challenging system.