[en] A new technique for injecting an ion beam into a storage ring is presented. The idea arose in connection with high energy ion beam fusion where a large degree of transverse stacking in both planes would otherwise be necessary. The method involves accelerating a molecular ion such as HI⁺ but storing the atomic ion I⁺ by photodissociating the molecule at injection. The irreversibility of the reaction γ + HI⁺, H⁰ + I⁺ renders irrelevant Liouville's theorem, which, with standard injection, would prevent new beam from being injected into the same space as already circulating beam. Xenon flashlamp and ruby laser systems for accomplishing molecular ion dissociation (MID) are described