多体相互作用对固氖物态方程的影响  

On the Effects of Multi-body Interactions on the Equation of State of Solid Neon

作　　者：郑兴荣[1] 

机构地区：[1]陇东学院电气工程学院,甘肃庆阳745000

出　　处：《陇东学院学报》2015年第5期17-21,共5页Journal of Longdong University

基　　金：陇东学院青年科技创新项目基金(XYZK1501)

摘　　要：基于原子团簇理论与多体展开方法,运用从头算自洽场方法计算固氖面心立方结构（fcc）最邻近原子间距在1.65~3.00之间的两体、三体和四体相互作用能及其对物态方程的影响。结果表明：原子势能的多体展开级数是一交错级数,其中偶数体势对原子势的贡献为正,奇数体势对原子势的贡献为负;在R≥2.60的区间原子势能的多体展开式只需考虑两体势即可,在1.80≤R〈2.60的区间里原子势能的多体展开式需要考虑到三体势的贡献,在R〈1.80的区间原子势能的多体展开式需要考虑到四体势的贡献;只考虑两体相互作用时固氖的压缩特性表现过硬,考虑三体相互作用后基本上与实验结果吻合,压强范围已经达到目前的实验数据值（0~208GPa）,考虑到四体相互作用后对压强研究区间已经达到240GPa,而在高于240GPa以上的压强区域需要考虑更高多体相互作用才能准确地解释。Based on the atomic cluster theory and multi-body expansion method, this study, taking ab initio Hartree-Fock self consistent field technique in the atomic distance of 1.65 - 3.00A, calculates and re- searches the effects that the multi-body interactions energy which include two-body, three-body and four- body interactions have on the equation of state of face-centered cubic （fcc） solid neon. The results are shown that many-body expansion potential was an exchange convergent series, and the even many-body contributions to the cohesive energy were repulsive, whereas the odd many-body contributions to the cohe- sive energy were attractive. When the atomic distance is R I〉 2.60A, the interaction energy may be well described by two-body interactions. The atomic distance is between 1.80A - 2.60A,the three-body con- tribution in many-body expansion potential should be taken into consideration. Below 1.80A, the four- body contributions have to be included. The calculated isotherm is in good agreement with the experimen- tal value in the experimentally studied ranges of pressures （0 -208GPa） considering the two-body and three-body potentials, taking into account the four-body potential the pressure has been reached 240GPa. However it can be accurately explain the phenomenon of the present experiment at above 240Gpa consid- ering the five-body potential.

关 键 词：原子团簇理论 固氖 两体势 三体势 状态方程 

分 类 号：O641[理学—物理化学]