Production of dimeson atoms in high-energy collisions

. The production of two-meson electromagnetic bound states and free meson pairs π^+π^- , K^+K^- , π^+K^∓ in relativistic collisions has been considered. It is shown that using of exact Coulomb wave functions for dimeson atom (DMA) allows one to calculate the yield of discrete states with the desired accuracy. The relative probabilities of production of DMA and meson pairs in the free state are estimated. The amplitude of DMA transition from 1 S to 2 P state, which is essential for the pionium Lamb shift measurements, has been obtained.