首页 | 本学科首页   官方微博 | 高级检索  
     检索      

钙钛矿型CaSiO_3解压缩和重压缩过程的分子动力学模拟
引用本文:徐桦,陆文聪,邵俊,陈念贻.钙钛矿型CaSiO_3解压缩和重压缩过程的分子动力学模拟[J].化学学报,2003,61(9):1416-1419.
作者姓名:徐桦  陆文聪  邵俊  陈念贻
作者单位:[1]常熟理工学院化学系,常熟215500 [2]上海大学理学院化学系,上海200436
摘    要:用分子动力学模拟方法(MD)研究了300 K时钙钛矿型CaSiO_3,从高压到负压 的解压缩过程。MD模拟获得的P-V关系与实验数据相近,与已报道的MD模拟数据基 本一致,所得体积模量也在实验数据分布范围内。减压缩和重压缩的MD模拟数据与 实验结果相似。钙钛矿型CaSiO_3解压缩成非晶态时,存在两个结构破坏阶段:破 坏硅氧八面体和破坏钙氧二十面体。当钙氧二十面体被破坏后,重压缩不能得到钙 钛矿型结构。只要钙氧二十面体未被破坏,重压缩可恢复钙钛矿型结构。本研究得 到的结果尚未见相关报道。由MD模拟数据计算了CaSiO_3系统的红外光谱,分析这 些数据可知钙钛矿型CaSiO_3解压缩非晶化是一个二阶软模相变。研究表明钙钛矿 型CaSiO_3结构存在一个等容的亚稳极限,其解压缩非晶化是一个受动力学控制的 亚稳状态。

关 键 词:钙钛矿型结构  硅酸钙  非晶  红外分光光度法
修稿时间:2003年11月22

Molecular Dynamics Simulation of CaSiO_3 Perovskite on Decompression and Re-compression
Institution:Department of Chemistry, Changsu College of Science and Technology;Department of Chemistry, Shanghai University
Abstract:The decompression process of CaSiO_3 perovskite was studied with molecular dynamics (MD) simulation from high pressure to negative pressure. The computed equation of state for CaSiO_3 is in good agreement with the experimental data and the results of the MD simulation reported. The computed bulk modulus is within the range of the experimental data. The results of our MD simulation on decompression and recompression are similar to the experimental results. There are two stages in the collapse of CaSiO_3 perovskite under decompression: the breakage of SiO_6 octahedron and the breakage of CaO_(12) icosahedron. If the Ca-O icosahedron has not been destroyed, the collapsed CaSiO_3 perovskite on decompression can be recovered on recompression. If the Ca-O icosahedron has been destroyed, it is not recoverable on recompression. This is a new result in our MD simulation. The infrared spectrum of CaSiO3 perovskite has been calculated with MD data. It is shown that the non-crystallization of CaSiO_3 perovskite on decompression is a second transition of softening mode and kinetically controlled metastable process. It is well obeyed that there is an isochoris metastable limit in CaSiO_3 perovskite and the quadratic law (P - P_s) ~ ( V - V_s)~2.
Keywords:PEROVSKITE TYPE STRUCTURE  CALCIUM SILICATE  AMORPHOUS  IR
本文献已被 维普 等数据库收录!
点击此处可从《化学学报》浏览原始摘要信息
点击此处可从《化学学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号