The Nature of Electronic Coupling between Ferrocene and Gold through Alkanethiolate Monolayers on Electrodes:  The Importance of Chain Composition, Interchain Coupling, and Quantum Interference

2001 ◽  
Vol 105 (32) ◽  
pp. 7699-7707 ◽  
Author(s):  
Andrew M. Napper ◽  
Haiying Liu ◽  
David H. Waldeck
2019 ◽  
Author(s):  
Junjie Liu ◽  
Dvira Segal

Charge transfer in donor-bridge-acceptor (DBA) structures typically takes place through the combination of donor-bridge and bridge-acceptor overlap integrals forming an effective, indirect electronic coupling between the donor (D) and acceptor (A) moieties. Here, we examine the effects of an additional direct DA electronic coupling on charge transfer processes in DBA systems with local interaction to thermal baths. First, using the exact Nakajima-Zwanzig master equation (NZME) for the reduced density matrix, we rigorously define probability currents as the coherent part of the NZME, thereby allowing us to quantify the contribution of the different electronic pathways (direct and indirect) to the charge transfer dynamics. Focusing on two minimal DBA systems of three sites (V and L models), and adopting well-developed methods, we find that the interplay between different transfer pathways can be assessed by the McConnell formula in the weak systembath coupling regime. We then demonstrate that the combination of indirect and direct donor-acceptor coupling either enhances or leads to a destructive quantum interference effect on charge transport processes, depending on the energy landscape of the DBA system.<br>


2019 ◽  
Author(s):  
Junjie Liu ◽  
Dvira Segal

Charge transfer in donor-bridge-acceptor (DBA) structures typically takes place through the combination of donor-bridge and bridge-acceptor overlap integrals forming an effective, indirect electronic coupling between the donor (D) and acceptor (A) moieties. Here, we examine the effects of an additional direct DA electronic coupling on charge transfer processes in DBA systems with local interaction to thermal baths. First, using the exact Nakajima-Zwanzig master equation (NZME) for the reduced density matrix, we rigorously define probability currents as the coherent part of the NZME, thereby allowing us to quantify the contribution of the different electronic pathways (direct and indirect) to the charge transfer dynamics. Focusing on two minimal DBA systems of three sites (V and L models), and adopting well-developed methods, we find that the interplay between different transfer pathways can be assessed by the McConnell formula in the weak systembath coupling regime. We then demonstrate that the combination of indirect and direct donor-acceptor coupling either enhances or leads to a destructive quantum interference effect on charge transport processes, depending on the energy landscape of the DBA system.<br>


1999 ◽  
Vol 169 (4) ◽  
pp. 471 ◽  
Author(s):  
Z.D. Kvon ◽  
L.V. Litvin ◽  
V.A. Tkachenko ◽  
A.L. Aseev

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.


2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>


2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>


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