Ab initio and variational transition state approach to beta-C3N4 formation: kinetics for the reaction of CH3NH2 with H.
Ab initio and variational transition state approach to beta-C3N4 formation: kinetics for the reaction of CH3NH2 with H.
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DOI：
10.1021/jp0531661
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发表时间：
2005-09
期刊：
影响因子：
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通讯作者：
Qingzhu Zhang;R. Q. Zhang;K. S. Chan;I. Bello
中科院分区：
文献类型：
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作者：
Qingzhu Zhang;R. Q. Zhang;K. S. Chan;I. Bello
CH3NH2分子被认为是氮化碳薄膜合成中甲烷和氨混合物中的重要中间体或甲胺和氢气混合物中的前体。从 CH3NH2 中快速提取氢 (H) 是氮化碳薄膜化学气相沉积 (CVD) 中 HCN 或 CNH 形成的重要过程。首次采用从头算直接动力学方法研究了 β-C3N4 CVD 中使用的原子 H 从 CH3NH2 夺氢反应的能量和动力学特征。确定了该反应的两个主要过程：从 CH3 基团中提取 H 和从 NH2 基团中提取 H。在从头计算数据的基础上，在 200 至约 3000 K 的宽温度范围内，通过规范变分过渡态理论和小曲率隧道校正推导了每个通道的速率常数。将理论结果与现有实验数据进行了比较。
The CH3NH2 molecule has been considered as either an important intermediate in methane and ammonia mixtures or a precursor in methylamine and hydrogen mixtures in the synthesis of carbon nitride thin films. The fast Hydrogen (H) abstraction from CH3NH2 is an important process involved in the formation of HCN or CNH in the chemical vapor deposition (CVD) of carbon nitride thin films. The energetic and kinetic characteristics of the H abstraction reaction from CH3NH2 by atomic H used in CVD of beta-C3N4 were studied using ab initio direct dynamics methods for the first time. Two primary processes were identified for this reaction: H abstraction from the CH3 group and H abstraction from the NH2 group. On the basis of ab initio data, the rate constants of each channel have been deduced by canonical variational transition state theory with small-curvature tunneling correction over a wide temperature range of 200 to approximately 3000 K. The theoretical results were compared with available experimental data.