After excitation of selenium encapsulated in Y-zeolite with 476 nm radiation, decomposition of the initially present semiconductor chains is observed. The fragmentation is influenced by the nature of the cations that counterbalance the negative charges of the aluminosilicate framework of the zeolite, In La3+- and Nd3+- exchanged Y-zeolite, Se-2(-) is formed upon irradiation with 476 nm laser light while Se-3 is generated in the Ca2+-exchanged form under the same conditions. Both species are identified by their resonance Raman spectra. The vibrational constants obtained for the electronic ground state of Se-3 in Ca-Y are omega(0) = 315 cm(-1) and omega(0)x(0) = 0.5 cm(-1), the respective values for Se-2(-) in La-Y are omega(0) = 329 cm(-1) and omega(0)x(0) = 0.8 cm(-1).