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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Spin-Flip Reaction of Re + CH4sA Relativistic Density Functional Theory Investigation
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Spin-Flip Reaction of Re + CH4sA Relativistic Density Functional Theory Investigation

机译：Re + CH4s的自旋翻转反应相对论密度泛函理论研究

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摘要

To explore the reaction mechanisms of methane dehydrogenation by gas-phase Re atom, the sextet, quartet,and doublet potential energy surfaces have been performed using density functional theory (DFT) and zeroorder regular approximation relativistic corrections at the PW91/TZ2P level. The minimum energy reaction path is found to proceed through the following steps: 6Re + CH4 f ReCH4 (61) f H3CReH (42) f 4TS2/3 f H2CReH2 (43) f 2TS3/4 f HCReH3 (24). Also, the reaction path involves the spin inversion twice in the different reaction steps. To better understand the spin inversion processes, the low energy crossing point is determined with the help of the density functional fractional occupation number approach. The first spin inversion, from the sextet state to the quartet state, makes the activation of the C-H bond energetically spontaneous. The second transition from the quartet state to the doublet state facilitates the cleavage of the second C-H bond, lowering the barrier from 186.1 to 24.2 kJ/mol. The overall reaction is calculated to be exothermic by 149.8 kJ/mol, and the final products in three spin states are investigated by NBO analysis, to compare the Re-C bonds and the C-H bonds.
机译：为了探索气相Re原子进行甲烷脱氢的反应机理，已使用密度泛函理论（DFT）和PW91 / TZ2P零阶正则逼近相对论校正进行了六方，四方和双峰势能面的反应。发现最小能量反应路径通过以下步骤进行：6Re + CH4 f ReCH4（61）f H3CReH（42）f 4TS2 / 3 f H2CReH2（43）f 2TS3 / 4 f HCReH3（24）。同样，反应路径在不同的反应步骤中两次涉及自旋反转。为了更好地理解自旋反演过程，借助密度泛函分数占有数法确定了低能量穿越点。从六重态到四重态的第一次自旋反转使C-H键的活化能自发地激活。从四重态到二重态的第二次过渡促进了第二个C-H键的裂解，将势垒从186.1降低至24.2 kJ / mol。计算出整个反应以149.8 kJ / mol放热，并通过NBO分析研究了三种自旋态的最终产物，以比较Re-C键和C-H键。

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