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.
@article{arxiv.0804.1881,
title = {Single-electron counting spectroscopy: simulation study of porphyrin in a molecular junction},
author = {Sven Welack and Jeremy B. Maddox and Massimiliano Esposito and Upendra Harbola and Shaul Mukamel},
journal= {arXiv preprint arXiv:0804.1881},
year = {2015}
}