Dear All- I have a structure, which I am refining in TOPAS, which is currently defined only in terms of fractional coordinates, and I would like to convert to a rigid body model based on a Z-matrix.
Writing the Z-matrix presents no problem, but it is necessary to position and orient the molecule correctly in the unit cell. Presumably the translation component is just the fractional coordinates of the first atom in my Z-matrix, something like Translate(@ .1, @ .2, @ .3) if my first atom is at .1, .2, .3. Does anyone know how to go about getting the rotation part, ie the '?' parts in: Rotate_about_axes(@ ?, @ ?, @ ?) All best wishes, Simon Parsons
