Deformation energy electron densities

In Fig. 13 we also present the energetics of the ( He) cluster with a bubble at the equilibrium electron bubble radius, with inferred (Section III.C) from the electron bubble. These results manifest the marked increase of Ec/N upon bubble formation, which is due to cluster deformation. Data were obtained on the bubble radius Rb, the cluster deformation energy per atom Ea/N [Eq. (57)], the cluster mean density n, and the cluster radius R for ( He)jy clusters. These results reflect on the energetic implications (i.e., the increase of E /N) and on the structural manifestations (i.e., cluster expansion with increasing the bubble radius). 

The diagonal terms yvv model the dependence of the total energy on charge density fluctuations of the second order. The monopole approximation restricts the change of the electron density considered, and no spatial deformations are included. Only the change of energy with respect to... 

The relaxation or deformation of the density cloud has an energetic consequence. The redistribution of electron density that accompanies the formation of the complex stabilizes the system, thus contributing to the interaction energy. In order to... 

In addition to electrostatic, exchange, and induction (a.k.a. deformation) energy, the fourth principal contributor to the interaction energy is the so-called dispersion energy [39]. This quantity is closely related to the London forces that are well known from freshman chemistry texts that originate from instantaneous fluctuations of the electron density of one molecule, which cause a sympathetic series of instantaneous density fluctuations in its partner. Dispersion, by its very nature, is attractive. In terms of ab initio molecular orbital theory, the dispersion energy is not present at the SCF level, but is a byproduct of the inclusion of electron correlation into the calculation. The reader is hence alerted to the fact that calculations that do not include electron correlation (and there are many such, particularly in the early literature) cannot be expected to include this fourth, and sometimes very important, component of the noncovalent force. 

Another study focusing on the comparison between theoretical and experimental densities is that of Tsirelson el al. on MgO.133 Here precise X-ray and high-energy transmission electron diffraction methods were used in the exploration of p and the electrostatic potential. The structure amplitudes were determined and their accuracy estimated using ab initio Hartree-Fock structure amplitudes. The model of electron density was adjusted to X-ray experimental structure amplitudes and those calculated by the Hartree-Fock model. The electrostatic potential, deformation density and V2p were calculated with this model. The CPs in both experimental and theoretical model electron densities were found and compared with those of procrystals from spherical atoms and ions. A disagreement concerning the type of CP at ( , 0) in the area of low,... 

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