X-ray and Electron Diffraction Study of MgO

Abstract

Precise X-ray and high-energy transmission electron diffraction methods were used for the study of electron density and electrostatic potential in MgO crystals. The structure amplitudes were determined and their accuracy estimated using ab initio Hartree-Fock structure amplitudes as criteria. The electrostatic potential distributions, reconstructed using Fourier series from both X-ray and electron diffraction data, are in satisfactory mutual agreement and are similar to the theory. They, however, suffer from restricted experimental resolution and, therefore, the reconstruction of the electrostatic potential via an analytical structural model is preferable. The x model of electron density was adjusted to X-ray experimental structure amplitudes and those calculated by the HartreeFock method. The electrostatic potential, deformation electron density and the Laplacian of the electron density were calculated with this model. The critical points in both experimental and theoretical model electron densities were found and compared with those for procrystals from spherical atoms and ions. A disagreement 11 concerning the type of critical point at (Z,Z,0) in the area of low, near-uniform electron density is observed. It is noted that topological analysis of the electron density in crystals can be related with a close-packing concept.

On the Possibility of Kinetic Energy Density Evaluation from the Experimental Electron-Density Distribution

“…§ Independent atomic model. ¶ Abramov, Avilov, Belokoneva, Kitaneh, Feil, Tsirelson & Okamura (1995);Tsirelson, Avilov, Abramov, Belokoneva, Kitaneh & Feil (1997). ** Independent ionic model.…”

Iono‐Covalent Character of the Metal–Oxygen Bonds in Oxides: A Comparison of Experimental and Theoretical Data

“…Tsirelson et al [57] used the K model to describe the ED distribution in MgO. Interionic charge transfer was found, resulting in ionic charges of AE1:36e.…”

“…B=ICP nn and B=L correlations have been established for the following electronic configurations 3d 3 , 3d 7 tetrahedral and 3d 8 [168]. Menil [169] has shown that most of the 57 Fe Mössbauer isomer shifts in (FeO n ) and (FeF n ) polyhedra can be interpreted with the help of the concept of the inductive effect of the competing bond. This study has been completed for iron(III) compounds by associating optical data, Mössbauer isomer shifts with structural and magnetical data (Tab.…”

Interface structure governed by plastic and structural dissimilarity in perovskite La0.7Sr0.3MnO3 nanodots on rock-salt MgO substrates

“…8 Close inspection of the fine structure of the {101}-LSMO-poles (see inset in Fig. 2(a)) reveals that each pole is associated to four satellites lying along the [110] and [1][2][3][4][5][6][7][8][9][10] directions, indicating the occurrence of four additional orientation domains related to the precise cube-on-cube orientation by 2 to 5 tilts about the [110] and [1][2][3][4][5][6][7][8][9][10] axes. In order to determine the average in-plane strain state of the nanodots ensemble, we conducted XRD / -2h/x space mapping (/ is the azimuthal orientation) at a grazing incidence angle of 0.…”