Stable multiply charged molecular ions

Stable doubly ad triply charged molecules ions of the smallest heterocyclic aromatic compounds C4H4X (X=NH, O and S) have been observed. Ionisation energies have been measured and correlated with computed values. Structures, stabilities and vibrational frequencies for these multiply charged molecular ions were computed employing a self-consistent-field- molecular-orbital treatment. Stable structures found for these multiply charges ions possess charge distributed throughout each ion. Ionic binding energies of several eV have been calculated for these doubly and triply charged species.