CRYSTALLOGRAPHIC STUDIES OF PLASTIC CRYSTALS
CRYSTALLOGRAPHIC STUDIES OF PLASTIC CRYSTALS
复制标题
DOI：
10.1016/0022-3697(61)90079-8
复制
发表时间：
1961-01-01
影响因子：
4
通讯作者：
DUNNING, WJ
中科院分区：
文献类型：
--
作者：
DUNNING, WJ
在用X射线衍射法研究晶体结构的过程中，人们很早就认识到晶体并不是完美的。首先是静态缺陷，一维，二维和三维，例如点缺陷，如杂质和空位，边缘和螺旋位错，和堆垛层错。第二，在理想的完美晶体中，存在着可以被认为是无序的缺陷。1932年，Hm和~ Umbeier（1）假设有19种方式可以失去秩序，他们描述了每一种程度的秩序所产生的衍射图案;随着秩序的丧失，尖锐的衍射最大值退化为条纹，斑块和倒易空间中的三维扩散体积。我们在这里并不关心所有这些可能性，而主要关心热运动在使原子或分子团的位置不确定时对晶格中平均位置的影响。
IN TI-@ study of crystal structure by X-ray diffraction methods, it was recognized very early that crystals are not ideally perfect. First there are the static imperfections, one dimensional, two dimensional and three dimensional, exemplified by point defects such as impurities and vacancies, by edge and spiral dislocations, and by stacking faults. Secondly, there are the imperfections which may be conceived as the loss of order in an ideal perfect crystal. Hm and~ UMMACHER (l) in 1932 postulated that there were nineteen ways in which order could be lost and they characterized the kind of diffraction pattern which would result from every degree of order; as order is lost sharp diffraction maxima degenerate into streaks, patches and three dimensional diffuse volumes in reciprocal space. We are not concerned here with all these possibilities but mainly with the effects of thermal motions in rendering indefinite the positions of the atoms or molecular groups about mean positions in the lattice.