Time-dependent density functional study of transport in molecular junctions

Electron transport in nanostructures is calculated and compared using a time-independent and a time-dependent first-principles framework. The time-independent approach uses the nonequilibrium Green's-function technique to calculate the current, while the time-dependent method extracts the current from the time propagated wave function. The approaches have been tested using gold-benzene-dithiolate-gold and gold-bipyridine-gold molecular junctions. The reasons for the differences in the current-voltage curves predicted by the two methods are discussed.