Calculating HOMO-LUMO energies at different bias voltages in molecular junction

[rupen_86]

kindly respond about how to find orbital energies or plot molecular energy spectrum at different bias voltages

PFA table showing orbital energies as a function of bias voltages.

[Petr Khomyakov]

I think the best way would be to calculate the transmission spectrum at different bias voltages, see the following tutorial http://docs.quantumwise.com/tutorials/molecular_device/molecular_device.html. The molecular energy levels correspond to electron transmission peaks.

I would like to notice that if the coupling between the molecule and electrodes is sufficiently strong, then there might exist a significant broadening of the molecular levels, i.e., the energy spectrum is no longer discrete as in the case of an isolated molecule. 

[rupen_86]

thanks for reply ... yeah i have calculated transmission spectrum at different bias voltages and there is consederable broadening of molecular levels but how can i deduce HOMO and LUMO energies from that transmission spectrum plot at different bias voltages....?? coz molecular energy spectrum analysis block gives orbital energies only at zero bias and my purpose is to tabulate orbital energies w.r.t bias voltage.

[Petr Khomyakov]

I think you may still try doing the Molecular Projected Self-Consistent Hamiltonian (MPSH) analysis (described in the tutorial) for the molecular junction at nonzero bias voltages. Calculating Projected Device Density of States would complement this analysis, as you might also be able to see some PDDOS peaks related to molecular levels.