Related Experiment Video
Updated: May 16, 2026
12:05
A Simple, Robust, and High Throughput Single Molecule Flow Stretching Assay Implementation for Studying Transport of Molecules Along DNA
Published on: October 1, 2017
Time-dependent view of sequential transport through molecules with rapidly fluctuating bridges
Bogdan Popescu1, P Benjamin Woiczikowski, Marcus Elstner
1School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
Physical Review Letters
|December 11, 2012
Summary
Molecular fluctuations in junctions can cause incoherent charge transport. Time-dependent methods are necessary, as averaged approaches like Landauer
Area of Science:
- Quantum chemistry
- Materials science
- Condensed matter physics
Background:
- Molecular junctions are susceptible to significant fluctuations due to solvent interactions.
- These fluctuations affect site energies and couplings, impacting charge transport.
- Incoherent effects in charge transport arise from these dynamic molecular changes.
Purpose of the Study:
- To compare the accuracy of a snapshot-averaged Landauer approach with a time-dependent Green's function scheme for charge transport.
- To evaluate the suitability of different theoretical methods for systems with dynamic molecular bridges.
Main Methods:
- Utilized molecular dynamics simulations to sample fluctuations in molecular junctions.
- Compared a snapshot-averaged Landauer approach with a time-dependent Green's function scheme.
- Analyzed charge transport in systems with rapidly varying molecular conformations.
Main Results:
- Snapshot-averaged methods, like the Landauer approach, are inadequate for systems with rapidly fluctuating bridges.
- Time-dependent schemes are crucial for accurately describing charge transport when conformational changes are rapid.
- Sequential transport is dominant in systems with rapidly varying bridge conformations.
Conclusions:
- The time-dependent Green's function scheme is more appropriate than the Landauer approach for charge transport in dynamic molecular junctions.
- Accurate modeling of charge transport requires methods that account for the time-order of conformational fluctuations.
Related Concept Videos
01:27Fast Reactions
Fast reactions occurring in times shorter than the time needed to mix reactants pose a unique challenge for investigation. In a liquid-phase continuous-flow system, reactants A and B are swiftly pushed into the mixing chamber, where mixing occurs within 1 ms. The reaction mixture then flows through an observation tube, and one measures light absorption to determine species concentrations at various points of the tube. This method is most appropriate when relatively large volumes of reactants...
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
01:24Protein Diffusion in the Membrane
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
02:39The Integrated Rate Law: The Dependence of Concentration on Time
While the differential rate law relates the rate and concentrations of reactants, a second form of rate law called the integrated rate law relates concentrations of reactants and time. Integrated rate laws can be used to determine the amount of reactant or product present after a period of time or to estimate the time required for a reaction to proceed to a certain extent. For example, an integrated rate law helps determine the length of time a radioactive material must be stored for its...
01:17Passive Diffusion: Overview and Kinetics
Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
01:25Transition State Theory
Transition-state theory, also known as activated-complex theory, provides a molecular-level explanation of reaction rates in both gas-phase and solution-phase reactions. It extends earlier kinetic models by considering the formation of a short-lived, high-energy configuration during a reaction.The progress of a chemical reaction can be represented using a reaction profile, which plots potential energy against the reaction coordinate. As two reactant molecules approach one another, their...