Fischer, A;Tiana, D;Scherer, W;Batke, K;Eickerling, G;Svendsen, H;Bindzus, N;Iversen, BB

2011

November

The Journal of Physical Chemistry A

Experimental and Theoretical Charge Density Studies at Subatomic Resolution

Validated

WOS: 46 ()

MOLECULAR-ORBITAL METHODS ELECTRON POPULATION ANALYSIS ACCURATE DIFFRACTION DATA GAUSSIAN-TYPE BASIS NET ATOMIC CHARGES RADIAL FUNCTIONS WAVE-FUNCTIONS TOPOLOGICAL ANALYSIS ORGANIC-MOLECULES BASIS SETS

115

13061

13071

Analysis of accurate experimental and theoretical structure factors of diamond and silicon reveals that the contraction of the core shell due to covalent bond formation causes significant perturbations of the total charge density that cannot be ignored in precise charge density studies. We outline that the nature and origin of core contraction/expansion and core polarization phenomena can be analyzed by experimental studies employing an extended Hansen-Coppens multipolar model. Omission or insufficient treatment of these subatomic charge density phenomena might yield erroneous thermal displacement parameters and high residual densities in multipolar refinements. Our detailed studies therefore suggest that the refinement of contraction/expansion and population parameters of all atomic shells is essential to the precise reconstruction of electron density distributions by a multipolar model. Furthermore, our results imply that also the polarization of the inner shells needs to be adopted, especially in cases where second row or even heavier elements are involved in covalent bonding. These theoretical studies are supported by direct multipolar refinements of X-ray powder diffraction data of diamond obtained from a third-generation synchrotron-radiation source (SPring-8, BLO2B2).

WASHINGTON

1089-5639

10.1021/jp2050405