  The shifts of the electronic absorption spectra of GaAs and GaP semiconductor
clusters are calculated using accurate pseudopotentials. In the absence of
experimental data at present, these calculations provide estimates of expected
spectral shifts in these clusters. In addition, these calculations show that
Coulomb interaction between the electron and hole dominates over the
confinement energy in small clusters, with the result that the electronic
absorption spectra of small clusters exhibit redshift instead of blueshift as
the cluster size is decreased.
