Charge distribution of the PAHs considered in our study. The contribution from each ionization state is shown as a function of the ionization parameter γ≡ for coronene (left panel), circumcoronene (middle panel) and circumcircumcoronene (right panel) derivatives. The color scheme is the same for all panels. Dashed grey lines are at A_V = 1, 2 and 4. As observed from the panels, the main charge states throughout the cloud are the neutrals (Z = 0), anions (Z = −1) and cations (Z = 1). Higher positively charged states are only present in minor levels at the surface of the NW PDR of NGC 7023. Higher anionic states (Z< −1) are not observed.