Many-electron correlations in computations of sodium atom photoabsorption

The role of many-electron correlations in photoabsorption processes has been investigated. The results of numerical computations of photoionization cross sections of sodium atom are presented. The many-body effects such as interchannel correlations resulting in autoionization resonance peaks, as well as effects of atomic core polarization were taken into account in the computations in terms of RPAE. Polarization corrections were accounted for using both static and dynamic polarization potentials. The influence of correlations on the position and the form of resonance peaks was studied. The obtained results demonstrate necessity of taking into account polarization effects, especially for clarification of autoionization resonance peaks position and the cross-section magnitudes in the low energy range. The best agreement with experimental data was reached with the model of dynamic polarization potential based on Dyson equation

Plasmon Resonance in Photoabsorption of Colloidal Highly Doped ZnO Nanocrystals

Abstract A new type of dipole plasmon excitations in colloidal highly doped ZnO nanocrystals has been studied by means of many-body quantum mechanical approach. We demonstrate that in photodoped ZnO nanocrystals, the conduction band electrons are localized close to the surface and the plasmon oscillations are induced by their angular motion. The transition of this plasmon mode from classical to quantum regime is defined by the nanocrystal size. The size dependence of the resonance frequency which results from quantum effects is in remarkable agreement with experimental observations

On stability of nanoscale electron-positron droplets

This paper presents the results of the total energy calculation for electroneutral electron-positron clusters with closed shells. The calculations were performed within the Random Phase Approximation with Exchange to take into account the many-particle correlations. The results show that the calculated energies per one electron-positron pair are lower than the corresponding energy per one pair of dipositronium molecule. The most stable electron-positron clusters are found for the cluster sizes in the interval of 20–40 pairs