(a) Recognition tunneling. Recognition molecules (ICA) covalently bound to gold electrodes, form transient hydrogen bonds (dashed lines) with a DNA base (Guanosine in this example) to bridge the gap between the electrodes. This complex serves as the model system for the NEGF simulation of the recognition tunneling current signals described here. (b) A much more complex pattern of hydrogen bonds emerges when the complex is embedded in a bath of 90 water molecules. Color key: red-oxygen, white-hydrogen, blue-nitrogen, grey-carbon, yellow-gold atoms.