空间群符号的变换及其变换程序

SPACE GROUP SYMBOLS AND THEIR TRANSFORMATION

为满足计算机检索的需要,新的晶胞选取原则对低级晶族矿物额外增加了限制条件,斜方晶系要求满足不等式 c<a<b;单斜晶系要求c>a,β角在90°—120°之间;三斜晶系要求 c<a<b,α,β角在90°—120°之间,γ角在60°—120°之间。斜方晶系同一空间群类型不同晶体取向最多可有六种不同的空间群符号,晶体从一种取向转化为另一种取向,其空间群符号和等效点系坐标都要发生相应的变化,本文用 C 语言编写了不同晶体取向之间空间群符号相互自动转换的计算机程序。

Besides conventional conditions,the standardized setting of 2 lattice for compute identi- fication of minerals lays on extra restrictions which are:(1)c<a<b,90°≤α&β≤120°,60° ≤γ≤120°for anorthic system;(2)c<a,90°<β≤120°for monocliniic system;(3)c<a< b for orthorhombic system.In orthorhombic system,one space group type may have six kinds of symhols from different setting of a lattice.Space group symbols and equivalent positions should be changed according to the setting transformation of a lattice.A computer program are designed in this paper for transformation of space group symbols.