2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29481We investigate the effects of the shape of quantum dots on their far-infrared absorption in an external magnetic field by a model calculation. We focus our attention on dots with a parabolic confinement potential deviating from the common circular symmetry, and dots having circular doughnut shape. For a confinement where the generalized Kohn theorem does not hold we are able to interprete the results in terms of a mixture of a center-of-mass mode and collective modes reflecting an excitation of relative motion of the electrons. The calculations are performed within the time-dependent Hartree approximation and the results are compared to available experimental results.RevTeX, 16 pages with 10 postscript figures included. Submitted to Phys. Rev. BMesoscale and Nanoscale Physicstext