论文标题
CH3OH+H-> CH2OH+H2中的低温动力学同位素效应在太空中甲醇的脱位亮起
Low-Temperature Kinetic Isotope Effects in CH3OH+H -> CH2OH+H2 Shed Light on the Deuteration of Methanol in Space
论文作者
论文摘要
我们使用激体顿方法计算了包括氢抽象反应的原子隧道CH3OH+H-> CH2OH+H2的反应速率常数。势能由一个神经网络拟合，该神经网络经过训练为UCCSD（T）-F12/VTZ-F12数据。使用Microcanonic Instanton理论计算双分子气相速率常数。研究了CH3组和传入H原子上的所有H/D同位素模式。对于所有同位素模式，均显示了代表表面上反应的单分子反应速率常数。在30 K处，它们的范围从4100次，用于替换抽象的H到〜8，用于替换抽象的H到次级KIE的大约2--6。 $^\ text {12} $ c/$^\ text {13} $ c动力学同位素效应在30 k时为1.08，而$^\ text {16} $ o/$^\ text {18} $ o/$ o/$ o/$ o o/$ o o/$ o动力学同位素效应的效果很小。使用这些数据的简单动力学表面模型预测了甲醇氘代形式的高丰度。
We calculated reaction rate constants including atom tunneling for the hydrogen abstraction reaction CH3OH+H -> CH2OH+H2 with the instanton method. The potential energy was fitted by a neural network, that was trained to UCCSD(T)-F12/VTZ-F12 data. Bimolecular gas-phase rate constants were calculated using microcanonic instanton theory. All H/D isotope patterns on the CH3 group and the incoming H atom are studied. Unimolecular reaction rate constants, representing the reaction on a surface, down to 30 K, are presented for all isotope patterns. At 30 K they range from 4100 for the replacement of the abstracted H by D to ~ 8 for the replacement of the abstracting H to about 2--6 for secondary KIEs. The $^\text{12}$C/$^\text{13}$C kinetic isotope effect is 1.08 at 30 K, while the $^\text{16}$O/$^\text{18}$O kinetic isotope effect is vanishingly small. A simple kinetic surface model using these data predicts high abundances of the deuterated forms of methanol.
