  We study the effect of Coulomb correlation on the emission properties of the
ground state exciton in zincblende CdSe/ZnS core-shell and in wurtzite ZnO
quantum dots. We validate our theory model by comparing results of computed
exciton energies of CdSe/ZnS quantum dots to photoluminescence and scanning
near-field optical microscopy measurements. We use that to estimate the
diameter of the quantum dots using a simple model based on infinitely deep
quantum well and compare the results with the statistics of the atomic force
microscopy scans of CdSe/ZnS dots, obtaining excellent agreement. Thereafter,
we compute the energy fine structure of exciton, finding striking difference
between properties of zincblende CdSe/ZnS and wurtzite ZnO dots. While in the
former the fine structure is dominated by the dipole terms of the multipole
expansion of the exchange interaction, in the latter system that is mostly
influenced by Coulomb correlation. Furthermore, the correlation sizeably
influences also the exciton binding energy and emission radiative rate in~ZnO
dots.
