Estimating temperature-dependent anisotropic hydrogen displacements with the invariom database and a new segmented rigid-body analysis program
| Autor: | Birger Dittrich, Jens Lübben, Luc J. Bourhis |
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| Rok vydání: | 2015 |
| Předmět: |
ONIOM
segmented rigid-body analysis Materials science Database Computation Neutron diffraction Rigid body computer.software_genre Research Papers General Biochemistry Genetics and Molecular Biology Displacement (vector) Vibration anisotropic displacement parameters generalized invariom database Neutron Anisotropy computer |
| Zdroj: | Journal of Applied Crystallography |
| ISSN: | 1600-5767 |
| Popis: | A novel method and a new program for estimating anisotropic displacement parameters for H atoms are presented. Results are validated against molecular orbital computations and neutron diffraction data. Invariom partitioning and notation are used to estimate anisotropic hydrogen displacements for incorporation in crystallographic refinement models. Optimized structures of the generalized invariom database and their frequency computations provide the information required: frequencies are converted to internal atomic displacements and combined with the results of a TLS (translation–libration–screw) fit of experimental non-hydrogen anisotropic displacement parameters to estimate those of H atoms. Comparison with TLS+ONIOM and neutron diffraction results for four example structures where high-resolution X-ray and neutron data are available show that electron density transferability rules established in the invariom approach are also suitable for streamlining the transfer of atomic vibrations. A new segmented-body TLS analysis program called APD-Toolkit has been coded to overcome technical limitations of the established program THMA. The influence of incorporating hydrogen anisotropic displacement parameters on conventional refinement is assessed. |
| Databáze: | OpenAIRE |
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