[en] Asymptotic forms for the one-electron two-centre Coulomb problem are used to discuss the properties of pseudocrossings in the correlation diagram for the (Zsub(a)Zsub(b)) sup((Zsub(a) + Zsub(b) - 1)+) system. It is shown that discrepancies in different expressions for the energy gap at a pseudocrossing may be resolved by a proper consideration of the electron wavefunction normalisation. (author)