Single-electron counting spectroscopy: simulation study of porphyrin in   a molecular junction
  Electron counting of a single porphyrin molecule between two electrodes shows a crossover from sub- to super-Poissonian statistics as the bias voltage is scanned. This is attributed to the simultaneous activation of states with electron transfer rates spanning several orders of magnitude. Time-series analysis of consecutive single electron transfer events reveals fast and slow transport channels, which are not resolved by the average current alone. 
Sven Welack, Jeremy B. Maddox, Massimiliano Esposito, Upendra Harbola,   Shaul Mukamel