Understanding Single-Molecule Parallel Circuits on the Basis of Frontier Orbital Theory

2020 ◽  
Vol 124 (5) ◽  
pp. 3322-3331 ◽  
Author(s):  
Kazuki Okazawa ◽  
Yuta Tsuji ◽  
Kazunari Yoshizawa
Keyword(s):  
Single Molecule ◽  
Frontier Orbital ◽  
Orbital Theory ◽  
Parallel Circuits

Biodegradation Mechanism of Anionic Polyacrylamide in Coal Preparation Using Molecular Simulation

2021 ◽  
Author(s):  
Fanglue Wang ◽  
Dongchen Zhang ◽  
Xuefeng Wu ◽  
Shengsong Deng
Keyword(s):  
Hydrophobic Interactions ◽  
Interaction Mechanism ◽  
Docking Study ◽  
Binding Modes ◽  
Frontier Orbital ◽  
Orbital Theory ◽  
Orbital Analysis ◽  
Insight Into ◽  
Anionic Polyacrylamide ◽  
Rhodococcus Sp

Abstract Biodegradation of anionic polyacrylamide (HPAM) and polyacrylate (PAA) by key enzymes, such as amidase and bacterial laccase, have been reported. However, the interaction mechanism between HPAM or PAA and enzymes is still poorly unclear. Here, docking study was undertook to demonstrate the binding modes and interaction details for degradation of HPAM or PAA. Then, bioactivities between PAA and HPAM were compared with frontier orbital theory. The docking results showed that HPAM completely buried in pocket of Rhodococcus sp. N-771 amidase (Rh Amidase), while most of PAA molecule exposed outside pocket of Bacillus subtilis laccase ( B. subtilis laccase ), further suggesting PAA was much more difficult to degrade than HPAM. Hydrophobic interactions and hydrogen bonds were necessary for stabilizing HPAM-Rh Amidase or PAA- B. subtilis laccase complex. The frontier orbital analysis indicated that bioactivity of PAA was higher than that of PAA. These findings provide an insight into enzyme-catalyzed degradation of HPAM. It is helpful in designing highly efficient enzymes against HPAM or PAA to protect environment.

Quantitative frontier orbital theory

1982 ◽  
Vol 86 (4) ◽  
pp. 301-314 ◽  
Author(s):  
Robert J. Elliott ◽  
Valerie Sackwild ◽  
W.Graham Richards
Keyword(s):  
Frontier Orbital ◽  
Orbital Theory

Single Molecule Rectification Induced by the Asymmetry of a Single Frontier Orbital

2014 ◽  
Vol 10 (8) ◽  
pp. 3393-3400 ◽  
Author(s):  
Wendu Ding ◽  
Christian F. A. Negre ◽  
Leslie Vogt ◽  
Victor S. Batista
Keyword(s):  
Single Molecule ◽  
Frontier Orbital ◽  
The Asymmetry

A graph-theoretical model for ballistic conduction in single-molecule conductors

2011 ◽  
Vol 83 (8) ◽  
pp. 1515-1528 ◽  
Author(s):  
Patrick W. Fowler ◽  
Barry T. Pickup ◽  
Tsanka Z. Todorova
Keyword(s):  
Single Molecule ◽  
Molecular Graph ◽  
Tight Binding ◽  
Transmission Function ◽  
Kekulé Structure ◽  
Qualitative Description ◽  
Frontier Orbital ◽  
Conduction Behavior ◽  
Ballistic Conduction ◽  
Source And Sink

The tight-binding version of the source-and-sink potential (SSP) model of ballistic conduction can be cast in a graph-theoretical form where the transmission through a molecular wire depends on four characteristic polynomials: those of the molecular graph and the vertex-deleted subgraphs with one or both of the molecular vertices contacting the electrodes removed. This gives an explicit function for the dependence of transmission on energy, one that is well adapted for qualitative description of general classes of conductors and conduction behavior. It also leads directly to a selection-rule criterion for conduction in terms of counting zero roots of the polynomials, which for benzenoids and graphenes is shown to subsume literature approaches based on Kekulé structure counting, bond order, and frontier-orbital matching. As explicitly demonstrated here, the SSP transmission function agrees with that derived by the Green’s function (GF) method.

scholarly journals Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3021
Author(s):  
Ivana Djurišić ◽  
Vladimir P. Jovanović ◽  
Miloš S. Dražić ◽  
Aleksandar Ž. Tomović ◽  
Radomir Zikic
Keyword(s):  
Transport Properties ◽  
Single Molecule ◽  
Density Functional ◽  
Tunneling Current ◽  
High Sensitivity ◽  
Orbital Energy ◽  
Frontier Orbital ◽  
Zero Bias ◽  
Electronic Tunneling ◽  
Tunneling Transport

The electrical current properties of single-molecule sensing devices based on electronic (tunneling) transport strongly depend on molecule frontier orbital energy, spatial distribution, and position with respect to the electrodes. Here, we present an analysis of the bias dependence of molecule frontier orbital properties at an exemplar case of DNA nucleotides in the gap between H-terminated (3, 3) carbon nanotube (CNT) electrodes and its relation to transversal current rectification. The electronic transport properties of this simple single-molecule device, whose characteristic is the absence of covalent bonding between electrodes and a molecule between them, were obtained using density functional theory and non-equilibrium Green’s functions. As in our previous studies, we could observe two distinct bias dependences of frontier orbital energies: the so-called strong and the weak pinning regimes. We established a procedure, from zero-bias and empty-gap characteristics, to estimate finite-bias electronic tunneling transport properties, i.e., whether the molecular junction would operate in the weak or strong pinning regime. We also discuss the use of the zero-bias approximation to calculate electric current properties at finite bias. The results from this work could have an impact on the design of new single-molecule applications that use tunneling current or rectification applicable in high-sensitivity sensors, protein, or DNA sequencing.

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