Miller Classification of Crystallographic Orientations: Transformation
The Miller classification is a system for describing the orientation of crystallographic planes and directions in a crystal lattice. It was developed by William Hallowes Miller in 1839.
Basic Principle:
The Miller classification uses three integers, typically denoted as (h, k, l), to represent the orientation of a crystallographic plane or direction. These integers are called the Miller indices.
Plane Orientation:
For a crystallographic plane, the Miller indices (h, k, l) represent the reciprocals of the intercepts that the plane makes with the three crystallographic axes (a, b, c).
Direction Orientation:
For a crystallographic direction, the Miller indices (h, k, l) represent the components of the direction vector along the three crystallographic axes.
Transformation Matrix:
To transform the Miller indices of a plane or direction from one Cartesian coordinate system to another, a transformation matrix is used. This matrix is derived from the orientation of the new coordinate system with respect to the original one.
Transformation Equations:
The equations for transforming the Miller indices (h', k', l') from the original coordinate system (a, b, c) to the new coordinate system (a', b', c') are as follows:
```
h' = h - u + k - v + l - w
k' = h - x + k - y + l - z
l' = h - r + k - s + l - t
```
where u, v, w, x, y, z, r, s, and t are the elements of the transformation matrix.
Applications:
The Miller classification of crystallographic orientations is widely used in crystallography, materials science, and condensed matter physics. It provides a systematic way to describe the orientation of crystallographic features, such as planes, directions, and lattice vectors, which is essential for understanding the structure and properties of crystals.