结晶生长的化学键合理论

Chemical Bonding Theory of the Crystal Growth

针对一般晶体的生长过程,在测定相应溶液(熔体)组成结构的基础上,我们引入了晶体生长过渡相区的概念,并采用键价模型来衡量生长过程中发生变化的化学键的键强度。过饱和溶液(熔体)中的生长单元经过生长过渡相区时,依据彼此之间弱的化学键合作用来微调其内部强的化学键,并以单个生长单元或者生长单元的简单连接体的形式键合进入晶格。在整个结晶生长过程中,生长单元之间弱的键合作用对整个结晶过程(生长速度、晶相的形成)起着决定性作用;同时,中等强度的化学键在生长过渡相区中的变化情况对晶体的最终形貌具有重要影响。

The concept of the transitional state zone was introduced to depict the crystallization process on the basis of the structure determination or analysis of the corresponding solution for the purpose of a comprehensive understanding of the crystallization. The strength of the chemical bonds formed in the crystallization process was calculated using the bond valence model. When the growth units attracted by the crystal surface pass through the transitional zone, the chemical bonds within these growth units are slightly modulated according to the weaker chemical bonds between growth units, and the growth units enter the crystal lattice site in a form of monomer or polymer. The weaker chemical bonds interconnecting these growth units play a crucial role in the whole growth process, while the changes of moderately strong chemical bonds within the transitional state zone have an important influence on the growth morphology.