We have used laser-photolysis/photoionization mass spectrometry to measure the kinetics of the reaction of 1-methylpropargyl (but-3-yn-2-yl,

) radicals with oxygen molecules as a function of temperature ($T=200-685\mathrm{K}$) and bath gas density ($1.2-15\times {10}^{16}{\text{cm}}^{-3}$). The low temperature (T ≤ 304 K) kinetics is dominated by oxygen addition to the

carbon of the radical to form a peroxyl radical, and the measured

bimolecular rate coefficient exhibits negative temperature dependence and depends on bath gas density. At slightly higher temperatures ($335-396\mathrm{K}$), where the redissociation rate of the peroxyl is already observable, we measured the

equilibrium constant as a function of temperature. At even higher temperatures ($T=479-685\mathrm{K}$), the loss rate of 1-methylpropargyl is determined by the addition of oxygen to the terminal

carbon and the reaction is observed to produce methylketene. The high-temperature

bimolecular rate coefficient is independent of bath gas density and the temperature dependence is weakly positive. To explain our experimental findings, we performed quantum chemical calculations together with master equation simulations. By using our experimental data to constrain key parameters, the master equation model was able to reproduce experimental results reasonably well. We then extended the conditions of our simulations up to 2000 K and 100 bar. The results of these simulations are provided in ChemKin compatible PLOG format.

中文翻译：

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1-甲基炔丙基与氧分子反应的动力学和热化学：实验和计算

我们已经使用激光光解/光电离质谱法来测量1-甲基炔丙基（but-3-yn-2-yl，

）具有氧分子的自由基随温度的变化（$Ť=200-685\mathrm{ķ}$）和镀液气体密度（$1.2-15\times {10}^{16}{\text{厘米}}^{-3}$）。低温（Ť  ≤304 K）动力学被氧除主导

自由基的碳形成一个过氧自由基，

双分子速率系数显示负温度依赖性，并取决于浴液气体密度。在稍高的温度下（$335-396\mathrm{ķ}$），在已经可以观察到过氧自由基的再离解速率的情况下，我们测量了

平衡常数随温度的变化。在更高的温度下（$Ť=479-685\mathrm{ķ}$），通过向末端添加氧气来确定1-甲基炔丙基的损失率

碳，观察到该反应产生甲基烯酮。高温

双分子速率系数与镀液中的气体密度无关，并且温度依赖性微弱为正。为了解释我们的实验结果，我们执行了量子化学计算以及主方程模拟。通过使用我们的实验数据来约束关键参数，主方程模型能够很好地再现实验结果。然后，我们将模拟条件扩展到2000 K和100 bar。这些模拟的结果以ChemKin兼容的PLOG格式提供。