rmat file format
The rmat file contains the
reciprocal axes matrix.
The RMAT keyword and data are obligatory, the other keywords
are optional.
Lines starting with # are ignored.
Syntax: RMAT bravaistype
Status: Required
bravaistype is one of ABCFIPR.
The matrix is build by the components of
the reciprocal axes (in the laboratory system) in columns with
all goniostat angles set to zero.
a*x |
b*x |
c*x |
a*y |
b*y |
c*y |
a*z |
b*z |
c*z |
Example:
RMAT P
0.09404740 0.06127740 -0.03415260
0.07703950 -0.07504390 -0.00808750
-0.06476710 -0.02511310 -0.05923030
Syntax: TMAT bravaistype pg
Status: optional
bravaistype is one of ABCFIPR.
pg is the pointgroup. See the
list of pointgroups.
The transformation matrix can be applied to
a dmat (direct axes matrix, the inverse of the rmat) or a
reflection indices vector.
The elements of the matrix are on the following line(s)
T11 |
T12 |
T13 |
T21 |
T22 |
T23 |
T31 |
T32 |
T33 |
Example:
RMAT P
0.09404740 0.06127740 -0.03415260
0.07703950 -0.07504390 -0.00808750
-0.06476710 -0.02511310 -0.05923030
TMAT P 2/m
1.00000000 0.00000000 0.00000000
0.00000000 0.00000000 -1.00000000
0.00000000 1.00000000 0.00000000
Syntax: CELL
a b c alpha beta gamma
Status: optional
These numbers are for documentation purposes only. The actual cell parameters
are always extracted from the rmat.
Syntax: SIGMA
a b c alpha beta gamma
Status: optional
Sigma's of cell parameters.
Syntax: QVECTYPE NONE/MODULATED/COMPOSITE
Status: optional
Sets the Qvectype. The default is NONE if no
QVEC's are defined and MODULATED is QVEC's are
defined.
Syntax: QVEC fh fk fl [order]
Status: optional
Adds a qvector to the qvector list.
fh fk fl are fraction numbers in terms of
a*, b* and c*
qvectors are combined to qvector combinations (QVC).
The optional order is the maximum order of the qvector.
If no QVC records are available, a set of qvector
combinations will be generated using order.
Syntax: QVC n1 n2 n3....
Status: optional
Defines a qvector combinaton. The number of arguments must be
equal to the number of qvectors.
If no QVC's are defined, a set of qvector
combinations will be generated.
Syntax: QVECRADIUS f
Status: optional
Overrules the maximum qvector radius (QVR).
If no qvector combinations (QVC) are defined, they will be generated.
- If only one qvector is defined, the order of that qvector determines
the the limits of the generated set of qvector combinations.
- If two or more qvectors are defined, the orders of the qvectors
and the maximum qvector radius (QVR) limit the generation of qvector
combinations.
- If no QVECRADIUS is specified, a default one
will be calculated:
For every qvector: multiply the qvector components with the
corresponding order and multiply the result with the rmatrix.
v =
R·(order*qv)
The resulting vector v is now defined in the
laboratory system, and it's length
1/d = 2*sin(θ)/λ
The (default) QVR
is set to the maximum value of 1/d of the contributing qvectors.
- Combinations of qvectors are generated, each qvector limited between
its own order.
- The resulting combination is only allowed if its 1/d is less than
the maximum QVR.