Study of the electron density in MgO, (Mg,Fe)O and Cu2O by Maximum Entropy Method and Multipole Refinements: comparison between methods

The electron densities determined by the maximum entropy method and by the multipole refinement approach are compared with each other, in terms of some topological properties according to the Bader formalism (Laplacian and eigenvalues of the Hessian matrix of the electron density at the critical points). The cases of MgO, (Mg,Fe)O and Cu2O are examined. The best agreement is observed for the critical points along the Mg-O, (Mg,Fe)-O and Cu-O directions, whereas larger discrepancies occur at the other critical points. Plots of the electron densities generated by the maximum entropy method and the multipole formalism along the most representative crystallographic directions contribute to elucidating the comparison between approaches.