...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Gas Phase Chemistry in Gallium Nitride CVD:Theoretical Determination of the Arrhenius parameters for the First Ga-C Bond Homolysis of Trimethylgallium
【24h】

Gas Phase Chemistry in Gallium Nitride CVD:Theoretical Determination of the Arrhenius parameters for the First Ga-C Bond Homolysis of Trimethylgallium

机译：氮化镓CVD中的气相化学：三甲基镓的第一次Ga-C键均解的Arrhenius参数的理论确定

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Experimental evidence suggests that the energy of activation for the first homolytic Ga-C bond fission of GaMe_3 of E_a=249 kJ/mol,measured by Jacko and Price in a hot-wall tube reactor,is affected by surface catalytic effects.In this contribution,the rate constant for this crucial step in the gas-phase pyrolysis of GaMe_3 has been calculated by variational transition state theory.By a basis set extrapolation on the MP2/ cc-pVXZ level and a correlation correction from CCSD(T)/cc-pVDZ level,a theoretical "best estimate" for the bond energy of DELTAH_(289)K=327.2 kJ/mol was derived.For the VTST calculation on the B3LYP/cc-pVDZ level,the energies were corrected to reproduce this bond energy.Partition functions of the transitional modes were approximated by a hindered rotor approximation to be valid along the whole reaction coordinate defined by the Ga-C bond length.On the basis of the canonical transition state theory,reaction rates were determined using the maxima of the free energy DELTAG.An Arrhenius-type rate law was fitted to these rate constants,yielding an apparent energy of activation of E_a=316.7 kJ/mol.The preexponential factor A=3.13X10~(16) 1/s is an order of magnitude larger than the experimental results because of a larger release of entropy at the transition state as compared to that of the unknown surface catalyzed mechanism.
机译：实验证据表明，由Jacko和Price在热壁管式反应器中测量的E_a = 249 kJ / mol的GaMe_3的第一个均质Ga-C键裂变的活化能受表面催化作用的影响。 ，利用变分跃迁状态理论计算了GaMe_3气相热解这一关键步骤的速率常数。通过对MP2 / cc-pVXZ水平进行基集外推和CCSD（T）/ cc-进行相关校正推导了pVDZ能级，得出了DELTAH_（289）K = 327.2 kJ / mol键能的理论“最佳估计”。对于B3LYP / cc-pVDZ能级的VTST计算，对能量进行了校正以重现该键能。过渡模的分配函数通过受阻转子近似来近似，在沿着由Ga-C键长定义的整个反应坐标上有效。在规范过渡态理论的基础上，使用游离态的最大值确定反应速率。能量消耗AG.Arrhenius型速率定律适用于这些速率常数，产生的表观活化能为E_a = 316.7 kJ / mol。指数前因子A = 3.13X10〜（16）1 / s比实验结果是因为与未知表面催化机理相比，过渡态的熵释放更大。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号