The electronic spectrum of the (SiSe)-Si-28-Se-80 Se molecule within 5 eV has been studied theoretically by using relativistic configuration interaction calculations which include pseudo potentials of the atoms. Potential energy curves of electronic states which correlate with the lowest dissociation limit have been constructed. Spectroscopic parameters of 11 A-S states are estimated and compared with the available observed data. The effects of the spin-orbit coupling on the potential curves and spectroscopic properties are discussed. Dipole moments of some of the low-lying states are computed. Transition dipole moments of some transitions such as E(1)Sigma(+)-X(1)Sigma(+) and A(1)Pi-(XE+)-E-1 are also calculated. The radiative lifetimes of A(1)Pi, E(1)Sigma(+), and 3(1)Sigma(+) states are reported. (C) 2003 Elsevier B.V. All rights reserved.