Abstract
We have studied electron correlation effects in quantum dots and rings which include a repulsive scattering centre and are subjected to a perpendicular magnetic field. The results for the dipole-allowed absorption spectrum show good qualitative agreement with the observed magnetoplasmon dispersion in similar systems. This work provides a unified description of the electron correlations in quantum dots and quantum rings in a magnetic field. We also demonstrate that optical absorption is a direct route to explore the effects of impurity and interactions in a quantum ring.