Structures, vertical excitation, and photoluminescence energies of the eight lowest electronic states of the [AlO4](0) defect in bulk SiO2 have been calculated using the complete active space self-consistent field, equation-of-motion coupled cluster, outer valence Green functions, and multireference configuration interaction methods within a cluster approximation. Two groups of electronic states with different types of the hole localization on oxygen atoms have been found. In two lower states the unpaired electron is localized on a single O atom, while in the higher energy states this electron is redistributed among two or three O atoms. The excitations to the second group of electronic states are accomplished by photoabsorption in the visible range, whereas photoluminescence energies lie in the infrared region due to significant Stokes shifts. (C) 2003 American Institute of Physics.