一类金属卤化物中孤对电子立体化学活性及其对双折射率的影响机制研究  

Study on stereochemical activity of lone pair electrons in a class of metal halides and its influence on birefringence

作　　者：朱越桐 吴昊 崔秀花[1] ZHU Yue-Tong;WU Hao;CUI Xiu-Hua(School of Physical Science and Technology,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学物理科学与技术学院,乌鲁木齐830046

出　　处：《原子与分子物理学报》2023年第6期152-162,共11页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(11864040);国家级大学生创新训练计划项目(202110755102)。

摘　　要：双折射材料广泛应用在激光通讯等工程和研究领域.本文使用第一性原理方法研究了后过渡金属卤化物PbX_(2)和BiX_(3)(X=Cl,Br,I)的电子结构与双折射率.计算结果表明,PbX_(2)和BiX_(3)(X=Cl,Br,I)中阳离子孤对电子立体化学程度自X=Cl至X=I逐渐减弱.原子轨道计算分析表明M s-X p(M为阳离子,X为卤素)轨道能级差值决定阳离子孤对电子立体化学活性程度;能级差值越大,孤对电子立体化学活性程度越弱.费米面附M p轨道极大影响材料双折射率的大小,因而使得这些材料的双折射率从X=Cl至X=I逐渐增强.Birefringent compounds are widely used in engineering and researching fields like optical fiber.The electronic structures and birefringences of the post-transition metal halides PbX_(2) and BiX_(3)(X=Cl,Br,I)were investigated by first-principles methods.The results show that the stereochemical activity of cations in PbX_(2) and BiX_(3)(X=Cl,Br,I)decreases gradually from Cl to I.The stereochemical activity of the cation is determined by the energy level difference of the cation s orbital and the halogen p orbital.The greater the difference in energy levels,the weaker the degree of stereochemical activity of lone pair electrons.The cation p states nearby the Fermi level mainly determine the birefringence,which make the birefringence of PbX_(2) and BiX_(3)(X=Cl,Br,I)gradually increase from CI to I.

关 键 词：第一性原理 孤对电子 双折射率 金属卤化物 

分 类 号：O437[机械工程—光学工程]