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The anatomy of a comprehensive constrained, restrained refinement program for the modern computing environment -
Luc J Bourhis1, Oleg V Dolomanov2, Richard J Gildea3
1Bruker AXS-SAS, 4 Allée Lorentz, 77447 Marne-la-Vallée cedex 2, France.
Acta Crystallographica. Section A, Foundations and Advances
|December 25, 2014
Summary
This paper details the mathematical foundation of olex2.refine, a new refinement engine for the Olex2 program. It provides equations for structure factors, derivatives, and various constraints and restraints for crystallographic refinement.
Area of Science:
- Crystallography
- Computational Chemistry
- Mathematical Modeling
Background:
- Crystallographic refinement is crucial for determining molecular structures.
- Existing refinement engines may have limitations in handling complex constraints and restraints.
- The Olex2 program is a widely used software for crystallographic data analysis.
Purpose of the Study:
- To describe the mathematical basis of the olex2.refine engine.
- To provide precise equations for all computations within the refinement engine.
- To introduce a framework for general constraints and new restraints on atomic displacement parameters.
Main Methods:
- Detailed mathematical derivations for structure factors and their derivatives.
- Formulation of various constraints and restraints, including those for twinning.
- Description of the engine's components and their interrelations.
- Development of a framework for general constraints with physical parameter dependencies.
Main Results:
- Comprehensive mathematical foundation for olex2.refine is presented.
- Equations for structure factors, derivatives, constraints, restraints, and twinning are clearly defined.
- A flexible framework for incorporating multiple general constraints is established.
- Novel restraints for atomic displacement parameters are introduced.
Conclusions:
- The olex2.refine engine provides a robust mathematical framework for crystallographic refinement.
- The described mathematical basis ensures accurate and reliable structure determination.
- The new framework and restraints enhance the capabilities of crystallographic refinement software.
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