Complexes of magnesium cation with cytosine were produced by laser ablation of a magnesia and cytosine mixture. Photoinduced reactions in the complexes of Mg+-cytosine have been studied at 230-440 nm. The evaporation product, Mg+, as well as other four and five reactive products were observed in the long and short wavelength regions, respectively. The ground state structures of the complexes composed of magnesium cation and the low-lying tautomers of cytosine were fully optimized at the B3LYP/6-31+G** level. The bond dissociation energies (BDEs) of the complexes for the channels we observed were calculated at the same theoretical level. (C) 2004 Elsevier B.V. All rights reserved.