高压固氩晶体构型与材料属性的研究  

Investigations of crystal configuration and material properties of high-compressed solid argon

作　　者：郑兴荣 李高清 田春山 李向富 ZHENG Xingrong;LI Gaoqing;TIAN Chunshan;LI Xiangfu(College of Electrical Engineering,Longdong University,Qingyang 745000,China;Department of Fundamental Courses,Qinghai University,Xining 810016,China)

机构地区：[1]陇东学院电气工程学院物理系,甘肃庆阳745000 [2]青海大学基础部,青海西宁810016

出　　处：《青海大学学报》2019年第6期71-79,共9页Journal of Qinghai University

基　　金：甘肃省教育厅高等学校创新能力项目(2019A-112);国家自然科学基金项目(11565018)

摘　　要：为研究面心立方结构(fcc)固氩的高压压缩特性和热力学特性,本文运用超分子单、双(三)重激发耦合簇理论(CCSD(T))ab initio法计算原子间距在2.0~3.3A下室温fcc固氩的多体相互作用势,得到固氩两体、三体和四体势团簇的构型以及两体和三体势的截断位置、收敛性、多体结合能和高压压缩特性,并与前期理论计算结果、实验值进行比较。结果表明:(Ar)2团簇的总原子数是903,属于12种不同的几何构型,(Ar)3是861,属于25种不同的几何构型,(Ar)4是816,属于28种不同的几何构型;仅考虑两体、三体项,且近邻原子数为42时,总多体势能Un在原子间距R≥2.3 A时收敛,而当R<2.3 A时,需要考虑四体项或者更多的近邻原子才能收敛;其多体展开式是一交换级数;零点振动能大约为总结合能的6%,已不可忽略。通过比较发现,本文的计算结果和实验数据在80 GPa内完全吻合。In order to study the high-compressed and thermodynamic properties of face-centered cubic(fcc)solid argon,using full single and double excitations plus perturbative treatment of triples(CCSD(T))ab initio method,we established and discussed the fcc atomic crystal configurations of two-,three-,four-body terms,and multibody potential energy of solid argon.The results show that the total number of(Ar)2 clusters is 903,belonging to 12 different geometric configurations;(Ar)3 is 861,belonging to 25 different geometric configurations,and(Ar)is 816,belonging to 28 different geometric configurations.The total potential energy Un reach saturation when R≥2.3 A and only consider two-,three-body interaction energy with 42 neighbor atoms;when R<2.3 A,it is necessary to consider four-body or more neighbor atoms to converge.Multibody expansion of fcc is an exchange series.The zero-point vibration energy is about 6%of the total cohesive energy,but it should not be neglected.Finally,by comparison,the calculated results are in good agreement with the experimental results within 80 GPa.

关 键 词：固氩 CCSD(T) 团簇构型 截断位置和收敛性 多体势 高压压缩特性 

分 类 号：O641[理学—物理化学] O561.1[理学—化学]