This chapter describes three modules which are implemented in the TNT refinement package, but are not used as often as the GEOMETRY and RFACTOR modules. These modules are:
The PHASE and REALSPACE modules require that phase information be present in the observed HKL file. This type of information is usually only needed in the early stages of refinement. Both of these modules appear to be useful when the placement of a known structure in a new crystal is being attempted. Test have been run using rigid body refinement of such structures which show that each of these modules is more powerful than the RFACTOR module.
It is not clear what relative weights should be given to each module when simultaneous refinement of several modules is performed. The user will have to experiment in this area.