金刚石附氢(100)面脱氢势垒的量子化学研究  

Quantum Chemical Study of Hydrogen Abstraction from a Diamond (100) Surface

作　　者：荣垂庆[1] 李延欣[2] 宋庆峰[1] 

机构地区：[1]空军长春飞行学院物理教研室,长春130022 [2]吉林大学原子与分子物理研究所,长春130023

出　　处：《物理化学学报》1996年第1期29-33,共5页Acta Physico-Chimica Sinica

基　　金：国家基础性研究重大关键项目!攀登计划;国家自然科学基金

摘　　要：采用MNDO（UHF）方法计算了金刚石（100）－（1×1）：2H双氢化表面和（100）－（2×1）：H单氢化表面的脱氢势垒，论证了决定金刚石附氢表面脱氢势垒大小的主要因素是气相－表面吸附氢原子间的相互排斥大小，得出（100）面两种表面结构脱氢势垒的理论预言值分别为71和59kJ·mol-1，均大于（111）面脱氢势垒的理论预言值42kJ·mol-1．揭示了在同等生长条件下金刚石（111）面可供成核和生长的反应基多于（100）面，与实验上得到的同等生长条件下（111）面的相对生长率大于（100）面的结论是一致的。Abstraction of terminal hydrogens on a diamond (100) surface by atomic hydrogen has been considered as a possible rate-determining elementary step in the mech anism of low-pressure diamond growth by chemical vapor deposition. The author used MNDO(UHF) methods to estimate the potential barrier for this abstraction reaction. It is predicted that the theoretical values of the potential barrier for H abstraction from full dihydride (100)-(1×1):2H and monohydride (100)-(2×1):H diamond surface are 71 and 59kJ·mol-1 respectively. The potential barrier for H abstraction from diamond (111) surface is smaller than those of diamond (100) surfaces. This results indicate that the creation of radical sites on diamond (111) surface via H abstraction is easier than that on (100) surface under the same growing condition. This conclution therefore supports the experimental result that the relative growth rate of (111) surface is greater than that of (100) surface.

关 键 词：脱氢势垒 分子轨道方法 金刚石 

分 类 号：O613.71[理学—无机化学] O641.121[理学—化学]