We have computed the dissociation energies for each of the charge states of the polyenes and annulenes and dissociation pathways given in Figure . As an example, the result is provided for the polyenes in Figure . We can think of the resulting map as a phase diagram in the size-maximal charge space: the positive dissociation energies correspond to thermodynamically stable polycations of a given size and charge, whether the negative ones are the thermodynamically unstable species that are prone to carbon backbone dissociation. To estimate more accurately the maximal charge at a given size for a given molecule, we can use the following approximation. First, determine the last stable integer charge Q of the molecule with dissociation energy D(Q) ≥ 0. Then, use a linear approximation of dissociation energy D in the range of charges between Q and Q + 1 to find the Q max from condition D(Q max ) = 0 as