Qvector
Qvectors are used to describe an incommensurate lattice.
- Qvectors are stored in rmat files.
- A qvector has 3 components qvx, qvy and qvz. These components
are fraction numbers in terms of
a*, b* and c*
- qvectors are combined into qvector combinations
(QVC). The coefficients of the qvectors
in such combinations are called m,
n and p.
- All the qvector combinations of a lattice form a list.
The index number in this list is called the qvector-combination-pointer
(QVP).
One qvector
The index for this qvector is called m.
The number of satellites for each reflection depends on the maximum order
of the qvector.
- order 1: m has values -1, 0 and 1
- order 2: m has values -2, -1, 0, 1 and 2
With one qvector the qvector-combinations (QVC) are limited to the
values of m.
Two qvectors
The index for these qvectors are called m and
n.
The number of satellites for each reflection depends on the maximum order
of each of the qvectors.
- order 1: m has values -1, 0 and 1.
- order 2: m has values -2, -1, 0, 1 and 2
With two qvectors the qvector-combinations (QVC) are build from
all available values of m and n.
If both qvectors are of order 1, there will be 9 qvector-combinations.
If both qvectors are of order 2, there will be 25 qvector-combinations.
| -1 |
-1 |
1 |
| 0 |
-1 |
2 |
| 1 |
-1 |
3 |
| -1 |
0 |
4 |
| 0 |
0 |
5 |
| 1 |
0 |
6 |
| -1 |
1 |
7 |
| 0 |
1 |
8 |
| 1 |
1 |
9 |