Renormalized molecular levels

Keywords Density functional theory (DFT) Green s functions Keldysh non-equilibrium Green s functions (NEGF) linear combination of atomic orbitals (LCAO) tunnel junction metal-fullerene-metal junction density of states (DOS) transmission function Landauer formula renormalized molecular levels (RMLs) I-V curves. 

Here, again, the sum runs over the atoms of the molecule and i/, p are their orbital quantum numbers, respectively. Obviously, the obtained eigen-levels and orbitals are different from those of the free molecule because the interaction with the leads is taken into account in Eq. (8) through H. The correspondence to the free molecule levels and orbitals can be found by projecting TJ( )1 ( onto the orbitals of the free molecule. This way, the terms HOMO-derived or LUMO-derived levels can be used for the corresponding groups of renormalized molecular levels. 

In Sections 2 and 3, we set up a formalism for dealing with the dynamics of dense fluids at the molecular level. We begin in Section 2 by focusing attention on the phase space density correlation function from which the space-time correlation functions of interest in scattering experiments and computer simulations can be obtained. The phase space correlation function obeys a kinetic equation that is characterized by a memory function, or generalized collision kernel, that describes all the effects of particle interactions. The memory function plays the role of an effective one-body potential and one can regard its presence as a renormalization of the motions of the particles. 

We briefly note from our computational approach the part relevant to electrode contributions. The contact effects due to the electrodes are to renormalize the electronic structure of the device molecule. The self-energy explicitly involves the contact effects on the molecule region due to the electrodes, so it plays a critical role in determining the transport characteristics its real/imaginary parts give rise to shift and broadening of the molecular energy levels. 

Neaton JB, Hybertsen MS, Louie SG (2006) Renormalization of molecular electronic levels at metal-molecule interfaces. Phys Rev Lett 97 216405... 

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