Scheme of many-body transitions associated with the measured ionic resonances of 5 para , together with STM images of assigned 5 para at biases where the corresponding transitions become accessible. Scanning parameters: I = 0.15 pA (V = −1.5 V) and 0.2 pA (V = 1.7 V). Centre inset: Laplace-filtered AFM image of assigned 5 para . STM setpoint: V = 0.2 V, I = 0.5 pA on bilayer NaCl, Δ z = −0.7 A. Here, the molecule is adsorbed on top of a defect on the surface. For an example of a 5 para species adsorbed adjacent to a third-layer NaCl island, see Supplementary Fig. 15. Also shown in the inset are seven bonds labelled a – g to highlight the bond-order differences between 5 para and 5 ortho . For the bond pairs a / b , c / d and e / f , the bonds labelled in bold exhibit a higher bond order than their neighbouring labelled bonds in 5 para .
