Excitation and fluorescence ultraviolet spectra of 12-group metal dimers (Zn₂, Cd₂ and Hg₂) recorded at several ultraviolet transitions provided information on potential energy curves of the ground and lower-lying excited electron energy states of the dimers. In experiments the dimmers were produced in free-jet supersonic beams and were excited in a vacuum chamber with a dye-laser beam. Well-resolved vibrational structures in excitation spectra, isotopic and rotational structures of the vibrational components as well as Condon internal diffraction patterns in fluorescence bands were recorded. Particularly, analyses of the fluorescence profiles yielded information on the repulsive parts of the ground-state interatomic potentials. In the case of Cd₂ and Hg₂, results confirmed a relatively soft repulsion between two metal atoms in the short-range region and made allowance for a covalent admixture to the ground-state van der Waals bonding.