Simple Estimates of the Electron Transport Properties of Molecules

We discuss how the complex bandstructure describes tunneling within a molecule, and how it can be used to understand single molecule conduction. Simple estimates of the conduction properties of some molecules can be obtained with minimal (or no) computational effort. Examples considered include tunneling current through SiO2, transistor action of biphenyl-dithiol, the effect of benzene ring rotation on tunneling through polyphenyl chains, and a “designed” molecule which – according to the form of its complex bandstructure – may function as a p-channel transistor.