A simple model of molecular electronic devices and its analytical solution

I present an analytically solvable model for molecular electronic devices (MEDs). The model contains all the essential components: semi-infinite contacts, molecule-contact interface, and of course, the molecule. I obtain explicit expression for the reflection coefficient r(E), as well as for the transmission probability T(E) [T(E)=1-mid R:r(E)mid R:(2)]. r(E) exhibits a surprisingly simple structure if studied as a function of a complex energy variable E. In this case, r(E) can be expressed in terms of a finite number of eigenvalues of a non-Hermitian Hamiltonian. This Hamiltonian also yields the molecular part of the MED wave function. Considering various MEDs, it is illustrated that the theory presented allows for a transparent interpretation of molecular conductance in terms of discrete eigenstates.