EFFECT OF ASYMMETRIC LATERAL LINKING GROUPS ON THE ELECTRONIC TRANSPORT IN MOLECULAR DEVICE

2021 ◽  
Author(s):  
YAMIN WU ◽  
BIN LIAO ◽  
GUOLIANG WANG ◽  
BAOAN Bian
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Electronic Transport ◽  
Density Functional ◽  
Molecular Junctions ◽  
Frontier Molecular Orbital ◽  
Asymmetric Distribution ◽  
Molecular Device ◽  
Functional Theory ◽  
Lateral Linking

The effect of asymmetric lateral linking groups on the electronic transport is investigated in the biphenyl molecule-based device with gold electrodes with the framework of density functional theory and nonequilibrium Green’s function. The asymmetric lateral linking groups reduce the currents of molecular junctions, and result in the reverse rectifying behavior. The devices with asymmetric lateral linking groups –SH and –SCH3 have maximum rectifying ratios, while the asymmetric lateral linking group –SH and –NH2 cause minimum rectifying ratios. The calculated results suggest that the asymmetric lateral linking group induces the reduced coupling between molecule and right electrode, asymmetric distribution of frontier molecular orbital and asymmetric evolution of the molecular orbital eigenenergies, accounting for the rectifying behavior.

Structure and electronic properties of GaN tubelike clusters and single-walled GaN nanotubes

2015 ◽  
Vol 29 (17) ◽  
pp. 1550116 ◽  
Author(s):  
Liren Liu ◽  
Yanbo Zou ◽  
Hengjiang Zhu
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Frontier Molecular Orbital ◽  
Structural Units ◽  
Functional Theory ◽  
Size Dependent ◽  
Molecular Orbital Surfaces

Extensive studies of the geometric structures, stabilities and electronic properties of gallium nitride (GaN)n tubelike clusters and single-walled GaN nanotubes (GaNNTs) were carried out using density-functional theory (DFT) calculations. A family of stable tubelike structures with Ga–N alternating arrangement was observed when n≥8 and their structural units (four-membered rings (4MRs) and six-membered rings (6MRs)) obey the general developing formula. The size-dependent properties of the frontier molecular orbital surfaces explain why the long and stable tubelike clusters can be obtained successfully. They also illustrate the reason why GaNNTs can be synthesized experimentally. Our results also reveal that the single-walled GaNNTs, which as semiconductors with a large bandgap, can be prepared by using the proper assembly of tubelike clusters.

scholarly journals Structural, Electronic, Molecular Orbital Analysis and Charge Distributions on Nitrate Salt of Guanidine through DFT and TD-DFT Methods

2021 ◽  
Vol 33 (8) ◽  
pp. 1905-1910
Author(s):  
S. Thangarasu ◽  
V. Siva ◽  
A. Shameem ◽  
A. Murugan ◽  
S. Athimoolam ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Ion Pairs ◽  
Frontier Molecular Orbital ◽  
Mulliken Charge ◽  
Functional Theory ◽  
Td Dft ◽  
Guanidinium Nitrate

Guanidinium nitrate, a non-linear optical material has been systematically studied through quantum chemical (density functional theory and Hartree Fock) methods. Studies on Mulliken charge, Frontier molecular orbitals (FMOs) and hyperpolarizability analyses have been performed. The Mulliken population analyses were carried out for the optimized molecular geometry by HF and B3LYP methods with 6-311++G(d,p) levels. The molecular orbital parameters of guanidinium nitrate have been calculated by FMO analysis. Frontier molecular orbital (FMO) analysis indicates the electron delocalization on the guanidinium nitrate and also its low value of energy gap indicates electron transfer. Optical property has been investigated by time-dependent density functional theory (TD-DFT) calculation. The second-order hyperpolarizability value of the ion pairs is much greater than urea, which confirms the good NLO nature of guanidinium nitrate.

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

High tunneling magnetoresistance induced by symmetry and quantum interference in magnetic molecular junctions

2021 ◽  
Author(s):  
Lin Huang ◽  
Yu-Jia Zeng ◽  
Dan Wu ◽  
Nan-Nan Luo ◽  
Ye-Xin Feng ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Green’S Function ◽  
Green's Function ◽  
Quantum Interference ◽  
Density Functional ◽  
Molecular Junctions ◽  
Tunneling Magnetoresistance ◽  
Functional Theory ◽  
Nonequilibrium Green's Function ◽  
Molecular Scale

Achieving high tunneling magnetoresistance (TMR) in molecular-scale junctions is attractive for their applications in spintronics. By using density-functional theory (DFT) in combination with the nonequilibrium Green's function (NEGF) method, we...

The Quantum Length Dependence of Conductance in Molecular Device: An Ab Initio Study

2010 ◽  
Vol 663-665 ◽  
pp. 519-522
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ying Tang Zhang
Keyword(s):  
Electronic Transport ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Molecular Device ◽  
Functional Theory ◽  
Length Dependence ◽  
Molecular Conductance ◽  
Homo Lumo ◽  
Molecular Compounds

By Applying Nonequilibrium Green’s Function Formalism Combined First-Principles Density Functional Theory, we Investigate the Electronic Transport Properties of Thiophene and Furan Molecules with Different Quantum Length. the Influence of HOMO-LUMO Gaps and the Spatial Distributions of Molecular Orbitals on the Electronic Transport through the Molecular Device Are Discussed in Detail. the Results Show that the Transport Behaviors Are Determined by the Distinct Electronic Structures of the Molecular Compounds. the Length Dependence of Molecular Conductance Exhibits its Diversity for Different Molecules.

A Density Functional Theory Study on the Ring-Opening Polymerization of D-Lactide Catalyzed by a Bifunctional-Thiourea Catalyst

2009 ◽  
Vol 62 (2) ◽  
pp. 157 ◽  
Author(s):  
Rong-Xiu Zhu ◽  
Ruo-Xi Wang ◽  
Dong-Ju Zhang ◽  
Cheng-Bu Liu
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Population Analysis ◽  
Density Functional Theory Calculations ◽  
Ring Opening Polymerization ◽  
Acyl Transfer ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Elimination Pathway

The thiourea-catalyzed methanolysis of d-lactide, a model system for the initiation and propagation of the organocatalyzed ring-opening polymerization (ROP) of lactide, has been studied by performing density functional theory calculations. Both the catalyzed and uncatalyzed reactions are explored along two possible pathways: one involves the stepwise addition–elimination pathway and the other is related to the concerted pathway. It is found that the reaction without the presence of the catalyst is difficult because the barrier involved is as high as 176 kJ mol–1. With the aid of a thiourea catalyst, the barrier is reduced to 88 kJ mol–1 with a preference for the stepwise addition–elimination mechanism over the concerted one. The role of the catalyst has been rationalized by analyzing the frontier molecular orbital interactions between the catalyst and substrates and by performing natural population analysis. Finally, another mechanism involving acyl transfer is discussed for the thiourea-catalyzed ROP.

scholarly journals Detection of adsorbed transition-metal porphyrins by spin-dependent conductance of graphene nanoribbon

RSC Advances ◽  
2017 ◽  
Vol 7 (46) ◽  
pp. 29112-29121 ◽  
Author(s):  
Peter Kratzer ◽  
Sherif Abdulkader Tawfik ◽  
Xiang Yuan Cui ◽  
Catherine Stampfl
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Electronic Transport ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Graphene Nanoribbon ◽  
Functional Theory ◽  
Metal Porphyrins

Electronic transport in a zig-zag-edge graphene nanoribbon (GNR) and its modification by adsorbed transition metal porphyrins is studied by means of density functional theory calculations.

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