IUCr journals

Towards the best model for H atoms in experimental charge-density refinement

Acta Cryst. (2009). A65, 300–311 (doi.org/10.1107/S0108767309019862)

[Charge-density refinement models]
Without neutron data, a mixed X-ray multipole refinement (high-order refinement of heavy atoms, low-angle refinement of H atoms and elongation of X-H distances to the average neutron values) supplemented by estimation of anisotropic thermal motion of H atoms gives the best topological and integrated properties of experimental ρ. Topological parameters calculated by using different models of H atoms should not be compared. Standardization of X-H distances to the average neutron data without any additional improvements of ADPs and X-H directions will not supply the correct topological parameters.

A. A. Hoser, P. M. Dominiak and K. Wozniak