TRANSFORM

2.3 - TRANSFORM - Transformation of Model and Data Files


This program allows the user to transform the unit cell (with errors), the reflection indices (and if present the direction cosines), the atomic coordinates and the anisotropic thermal parameters according to a chosen transformation matrix R. A new model file NEW.INS and reflection file NEW.HKL are written. A number of standard transformation matrices are available, but the user can type in any matrix of choice. If the determinant of R is negative, the cell volume is reported as negative, indicating that the resultant cell is not right-handed. A new space group may be chosen from the list of 530 standard and non-standard settings. For an explanation of the various settings see here.

For instance, suppose a user has collected data and refined a structure in the non-standard orthorhombic space group C2cb, and wishes to transform the structure to the standard setting. Looking down the list of space groups in the TRANSFORM menu shows that C2cb is space group #41 with setting -cba. To perform the transformation, the user merely needs to select the -cba matrix button, and then choose the standard setting for this spacegroup, which is Aba2. Clicking the OK button then gives transformed set (NEW.INS, NEW.HKL etc),which may be used for refinement without any further changes.

The TEST button allows the user to see the result of applying the matrix to the input cell.