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Al2O3晶体的壳层结构：Hexa vs Rhom

已有 400 次阅读 2026-3-30 12:02 |个人分类:AEC 原子环境计算|系统分类:科研笔记

Al2O3晶体的壳层结构：Hexa vs Rhom

电子在原子中，是一层一层的，这叫原子的壳层结构。

实际上，如果站在晶体的某个原子上看，周围原子也是一层一层的，这就是所谓的局域团簇结构。

下面左边的AEC数据，用的晶体结构实验数据(CIF)对应空间群的六方晶胞，下面右边的AEC数据，用的晶体结构实验数据(CIF)对应空间群的三方晶胞。如果让观察者H站在原子12c-Al上，让观察者R站在原子4c-Al上，H和R观察的原子环境是完全相同的，因为Hexa数据和Rhom数据描述的是同一个晶体Al2O3。原始的CIF实验数据，Hexa数据中的原子坐标有4位有效数字，Rhom数据中的原子坐标只有3位有效数字。因为两套晶体结构数据的实验误差，导致在AEC的计算中，距离参考原子越远，左边和右边原子环境的差别也越大。

文件头部 + Shell 1–4 完整排版

Hexa 数据（左）	Rhom 数据（右）
"AEC-SP-167-Hexa-Al2O3","Local-Cluster"	"AEC-SP-167-Rhom-Al2O3","Local-Cluster"
"AEC-SP-167-Hexa-Al2O3","delta=",.005	"AEC-SP-167-Rhom-Al2O3",0.005
"a=b=",4.7352,"c=",12.9176	"a=b=c=”, 5.128
"alpha=beta=",90, "gamma=",120	"alpha=beta=gamma=",55.27
"cell_formula_units_Z",6	"cell_formula_units_Z",2
"Cluster center:","12c-Al"	"Cluster center:","4c-Al"
"Cartesian coordinates:",0,0,-1.9092	"Cartesian coordinates:",0,0,-1.8838
"Space Group:",0,0,.3522	"Space Group:",.355,.355,.355

Shell 1

Hexa	Rhom
" Cluster shell No:",1	" Cluster shell No:",1
" distance from cluster center,d=",1.8443	" distance from cluster center,d=",1.8455
" ",1,"18e-O"	" ",1,"6e-O"
" ",-.7257,-1.4767,-1.076	" ",.7207,-1.4982,-1.0826
" ",.0268,-.3333,.2728	" ",.75,.053,.447
" distance from cluster center,d=",1.8445	" distance from cluster center,d=",1.8456
" ",2,"18e-O"	" ",2,"6e-O"
" ",1.6419,.1103,-1.076	" ",-1.6579,.125,-1.0826
" ",.3333,.3602,.2728	" ",.053,.447,.75
" distance from cluster center,d=",1.8447	" distance from cluster center,d=",1.8456
" ",3,"18e-O"	" ",3,"6e-O"
" ",-.9163,1.3672,-1.076	" ",.9372,1.3733,-1.0826
" ",-.3602,-.0268,.2728	" ",.447,.75,.053

Shell 2

Hexa	Rhom
" Cluster shell No:",2	" Cluster shell No:",2
" distance from cluster center,d=",1.9619	" distance from cluster center,d=",1.9845
" ",1,"18e-O"	" ",1,"6e-O"
" ",-1.4513,0,-3.2294	" ",-.7207,1.2483,-3.2479
" ",-.3065,-.3065,-.182	" ",-.053,.553,.25
" distance from cluster center,d=",1.962	" distance from cluster center,d=",1.9845
" ",2,"18e-O"	" ",2,"6e-O"
" ",.7257,1.2569,-3.2294	" ",-.7207,-1.2483,-3.2479
" ",0,.3065,-.182	" ",.25,-.053,.553
" distance from cluster center,d=",1.962	" distance from cluster center,d=",1.9845
" ",3,"18e-O"	" ",3,"6e-O"
" ",.7257,-1.2569,-3.2294	" ",1.4414,0,-3.2479
" ",.3065,0,-.182	" ",.553,.25,-.053

Shell 3

Hexa	Rhom
" Cluster shell No:",3	" Cluster shell No:",3
" distance from cluster center,d=",2.6404	" distance from cluster center,d=",2.7282
" ",1,"12c-Al"	" ",1,"4c-Al"
" ",0,0,-4.5496	" ",0,0,-4.612
" ",0,0,-.4608	" ",.145,.145,.145

Shell 4

Hexa	Rhom
" Cluster shell No:",4	" Cluster shell No:",4
" distance from cluster center,d=",2.7766	" distance from cluster center,d=",2.8036
" ",1,"12c-Al"	" ",1,"4c-Al"
" ",0,-2.7336,-2.3962	" ",0,-2.7465,-2.4467
" ",.3333,-.3333,-.006	" ",.645,-.355,.645
" distance from cluster center,d=",2.777	" distance from cluster center,d=",2.8037
" ",2,"12c-Al"	" ",2,"4c-Al"
" ",2.3676,1.3672,-2.3962	" ",-2.3786,1.3733,-2.4467
" ",.3333,.6667,-.006	" ",-.355,.645,.645
" distance from cluster center,d=",2.777	" distance from cluster center,d=",2.8037
" ",3,"12c-Al"	" ",3,"4c-Al"
" ",-2.3676,1.3672,-2.3962	" ",2.3786,1.3733,-2.4467
" ",-.6667,-.3333,-.006	" ",.645,.645,-.355