GroupTheory`CrystalStructure`

GTChangeCoord

GTChangeCoord[crystal structure]

changes the coordinates of the basis atoms of crystal structure from relative to the lattice vectors to Cartesian.

Details and Options

A series of crystal structures, frequently used in GTPack is stored in the database GTPack.struc In this database the positions of the basis atoms are given in Cartesian coordinates. More common is to give those positions in terms of the lattice vectors. Thus the database GTPackR.struc which extends the number of implemented structures a bit uses the formulation in fractions of the lattice constant.
A series of commands depends on the information in crystal structure. This extension of the structure definition is done in such a way, that you can use both types of databases and it will be internally realized what is to do.
If you construct your own datasets, you can mix the definitions. Note, the old list of crystal structure has length 8, i.e. in such a list Cartesian coordinates are used for the positions of the basis atoms. In the format the crystal structure list has length 9. The ninth elements indicates which kind of definition is used for the basis atoms: "R" - in fractions of lattice vectors, "C" - Cartesian coordinates.
The following option can be given:
GOVerbose False Controls the output of additional information
This command is new and not explained in:
W. Hergert, M. Geilhufe, Group Theory in Solid State Physics and Photonics. Problem Solving with Mathematica, chapter B.3

open allclose all

First, load the package:

We define the diamond crystal structure with atom positions given inCartesian coordinates in the old form.

The same definition of the atomic positions, but with the additional indication in the 9th element.

In both examples a recalculation is not necessary.

In the next structure file the positions are given in fractions of the lattice vectors.

The calculation to Cartesian coordinates is done.

The index of the type of data is wrong in this example. Thus, the calculation is stopped.

With GOVerbose->True additional information will be printed.