Charge density difference maps

The charge density difference maps from the Gunnarsson et al." calculations are compared with experiment107 and with Hartree-Fock results108 in Figure 12. There are differences between theory and experiment which are not presently resolved to the author s knowledge. 

Figure 12 Charge density difference maps 0/N2 from ref. 99, compared with HF results of ref. 108...

Charge-density difference maps from the band calculation (crystal minus superimposed free atoms) clearly show charge transfer, but the limited basis set precludes detailed comparison with experiment. 

Fig. 7. Maps of the electronic charge density in the (110) planes In the ordered twin with (111) APB type displacement. The hatched areas correspond to the charge density higher than 0.03 electrons per cubic Bohr. The charge density differences between two successive contours of the constant charge density are 0.005 electrons per cubic Bohr. Atoms in the two successive (1 10) planes are denoted as Til, All, and T12, A12, respectively, (a) Structure calculated using the Finnis-Sinclair type potential, (b) Structure calculated using the full-potential LMTO method.

Typical examples of density- and density difference maps for ion-molecule complexes are shown in Chapter V. For our purpose we do not need the detailed spatial information which is rather confusing for a discussion of charge transfer. We proposed therefore 113> to choose an axis of the complex (2-axis), which is characteristic for the type of interaction that we are interested in. In Li+... OH2 or Li+... OCH2 this is evidently the twofold symmetry axis C2. In other cases like e.g. F-... HOH or (H20)2, the connection line of the three atoms forming the hydrogen bond will be appropriate ). After defining a 2-axis in this way we can calculate a density difference curve Aq(z) by simple integration (35) ... 

Fig. 22. Total charge distribution and charge density differences upon formation of a HOH-F complex in the plane of the water molecule (maps are taken from Ref. 208>)...

Figure 1.17. Electron charge density difference contour map for CO on Ni(100) and CO on Ni(100)/H in atop sites, derived from DFT calculations.

Figure 1 The electronic density difference maps for the Be3 trimer partitioned for 2-body (a) and 3-body (b) contributions and the total difference density distribution (c). The plot is done in the plane of Be3. The spacing between the contours is 0.001 electron/bohr. The contour with no density charge axe labeled with zeros while solid lines indicate the enhancement of electronic density.

Conventional implementations of MaxEnt method for charge density studies do not allow easy access to deformation maps a possible approach involves running a MaxEnt calculation on a set of data computed from a superposition of spherical atoms, and subtracting this map from qME [44], Recourse to a two-channel formalism, that redistributes positive- and negative-density scatterers, fitting a set of difference Fourier coefficients, has also been made [18], but there is no consensus on what the definition of entropy should be in a two-channel situation [18, 36,41] moreover, the shapes and number of positive and negative scatterers may need to differ in a way which is difficult to specify. 

Examination of the multipole populations gives no indication of the discrepancy observed in the model maps, all populations from parallel refinements agreeing to within two esd s (Table 5). The one striking exception is the monopole population (P,) for carbon. This must be a simple difference in the partitioning of the charge density between atom centers in the model as there is no discernible difference in the model maps around the carbon position. 

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