The program calculates the correlation relations between the irreducible representations (irreps) of a group-subgroup pair. It takes into account all the points of the reciprocal space which are reduced to the Γ point in the low symmetry basis. Using this program one can study the behaviour of the Raman modes during a phase transitions.
One have to introduce the following information in the program:
The high and low symmetry structures can be introduced directly or in CIF format file. If you do not know the matrix which relates both structures you can use the program STRUCTURE RELATIONS which will give you the matrix you are looking for. One can introduce the transformation matrix in its matrix form or in abc form.
In the fist part of the output one can find the information that has been introduced, the high and low symmetry structure and the transformation matrix. After each structure there is information about the IR and Raman mode activity of the structure.
After this one can find the information about the wave-vectors of the high-symmetry which transform into the Γ point at the low-symmetry structure. One can also find the relation between the irreps of the high and low symmetry structure, the information about the IR and Raman activity and the Brillouin zone for the high symmetry structure.
At the end of the page one can find the correlation relation tables between those points.