The excitonic absorption spectrum of a single quantum dot is investigated t
heoretically and experimentally. The spectrum is determined by an interacti
ng electron-valence-hole complex. We show that the mixing of quantum config
urations by two-body interactions leads to distinct absorption spectra cont
rolled by the number of confined electronic shells. The theoretical results
are compared with results of photoluminescence excitation spectroscopy on
a series of single self-assembled In0.60Ga0.40As quantum dots.