Interferences in electron spectra produced by coherent emission from the two atomic centers of the H2 molecule are analyzed. Theoretical treatments in first and second order are presented for collisions of H2 with fast ions. To describe the basic features of the interferences, methods known from wave optics are used. Moreover, a full quantum treatment is given to determine in detail the amplitudes responsible for the interference effects. The theory is compared with recent experiments revealing interferences in first and second order.