ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
A systematic convergence test for constrained rigid-body least-squares refinement shows good possibility of convergence towards the right solution, even starting from strongly misplaced molecular models (translations of about 1.5 Å and rotations of about 30°), if an appropriate sequence of reflections and strategy is used. Consequently, a routine for solving structures with a known molecular model by ab initio least-squares refinement has been written, and successfully tested with three unknown structures: inclusion of second derivatives has also been tested, with a view to improving the method. In all cases so far examined, the routine is very fast, simple to use and competitive with usual methods, even when the model is only approximately known. The inclusion of second derivatives as such is not convenient, at least if precautions are not taken to reach a true minimum: a possible way of further improvement is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739481000119
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