A Comparison between Polyatecylene and Polycarbonitrile

1993 ◽  
Vol 48 (1-2) ◽  
pp. 159-164 ◽  
Author(s):  
Michael Springborg
Keyword(s):  
Comparative Study ◽  
Electronic Properties ◽  
Ground State ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Form Factors ◽  
Model Calculations ◽  
Densities Of States ◽  
Momentum Distributions

Abstract Results of a theoretical, comparative study of the electronic properties of trans-polyacetylene and polycarbonitrile are reported. Polyacetylene consists of zigzag chains of CH units, whereas polycarbonitrile has every second CH unit replaced by an N atom. Ground-state properties (structure, electronic bonds and bands, densities of states, momentum distributions, and reciprocal form factors) of the periodic, infinite, isolated chains are studied by means of first-principles, density-functional calculations. It is demonstrated how the presence of the (nitrogen) heteroatoms in the backbone of polycarbonitrile leads to a partial localization of the electrons. In order to investigate charged chains, model calculations are subsequently performed. These indicate solitons but not polarons to be stable. In total, the analysis demonstrates how the combination of information that can be obtained from various experiments provides a detailed description of the compounds.

The Studies of ScB2 (0001) Surfaces from the First-Principles

2014 ◽  
Vol 989-994 ◽  
pp. 688-693
Author(s):  
Hui Zhao ◽  
Qian Han
Keyword(s):  
Energy Density ◽  
Total Energy ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Surface Structures ◽  
Charge Accumulation ◽  
Total Energy Density ◽  
Energy Density Functional

We conduct first-principles total-energy density functional calculations to study the ScB2 (0001) surfaces. The optimized surface structures and electronic properties are obtained. The results show that Sc-terminated surface is thermodynamically more favorable in most of range. The relaxations indicate that it is mainly localized within top three layers and it is less relaxation for Sc-terminated surface. The surface induced features in DOS disappear slowly for the B-terminated surface but vanish rapidly for the Sc-terminated surface. For the Sc-terminated surface, it shows strong metallic property. Simultaneously, both termination surfaces are found charge accumulation relative to the idea surface. Sc-B bonds are strengthened result in the outermost interface spacing are all contracted.

First-Principles Investigation of Structural, Elastic and Electronic Properties of Lanthanide Titanate Oxides Ln2TiO5

2011 ◽  
Vol 1298 ◽  
Author(s):  
Hui Niu ◽  
Huiyang Gou ◽  
Rodney C. Ewing ◽  
Jie Lian
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Shear Moduli ◽  
Charge Densities ◽  
Young’S Moduli ◽  
Wide Range ◽  
Densities Of States ◽  
Complete Set

ABSTRACTSystematic first-principles calculations based on density functional theory were performed on a wide range of Ln2TiO5 compositions (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Y) in order to understand the correlation between structural, elastic and electronic properties. A complete set of elastic parameters including elastic constants, Hill’s bulk moduli, shear moduli, Young’s moduli and Poisson’s ratio, were calculated. All Ln2TiO5 are ductile in nature, and analysis of densities of states and charge densities suggests that the oxide bonds are highly ionic.

First-principles investigation of the Schottky contact for the two-dimensional MoS2 and graphene heterostructure

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60271-60276 ◽  
Author(s):  
Biao Liu ◽  
Li-Juan Wu ◽  
Yu-Qing Zhao ◽  
Ling-Zhi Wang ◽  
Meng-Qiu Cai
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Schottky Contact ◽  
Two Dimensional

The electronic properties of an MoS2 and graphene heterostructure are investigated by density functional calculations.

First Principles Based Study of Ground State and Electronic Properties of TmPb3 Intermetallic Compound

2016 ◽  
Vol 28 ◽  
pp. 43-46
Author(s):  
Gitanjali Pagare
Keyword(s):  
Intermetallic Compound ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
Density Of States ◽  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Full Potential ◽  
Electronic Band ◽  
Calculated Density

The ground state behavior of rare earth intermetallic compound TmPb3, which crystallize in AuCu3 type structure, has been examined using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. Very few study on structural and electronic properties of TmPb3 compound has been available in the literature, which motivated us to perform the present study. The spin polarized calculations are carried out within the PBE-GGA and LSDA for the exchange correlation (XC) potential. Our calculated ground state properties such as lattice constant (a0), bulk modulus (B) and its pressure derivative (B’) are in good agreement with the experimental results. The value of bulk modulus of TmPb3 is found to be 44.32 GPa and 55.01GPa by PBE-GGA and LSDA respectively. The electronic band structure (BS) and density of states (DOS) verify the metallic nature of this compound. The calculated density of states at the fermi level is found to be 0.16 states/eV and 19.50 states/eV for spin-up and spin-down modes respectively. The magnetic moment of TmPb3 is found to be 0.95.

scholarly journals Green Afterglow of Undoped SrAl2O4

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2331
Author(s):  
Bao-Gai Zhai ◽  
Yuan-Ming Huang
Keyword(s):  
First Principles ◽  
Density Functional Calculations ◽  
Glow Curve ◽  
Density Functional ◽  
Trap Depth ◽  
Peak Temperature ◽  
Solution Combustion ◽  
Densities Of States ◽  
Thermoluminescence Glow Curve ◽  
Trap Levels

Undoped SrAl2O4 nanocrystals were obtained via solution combustion using urea as fuel. The afterglow properties of undoped SrAl2O4 were investigated. Green afterglow from undoped SrAl2O4 is visible to the human eye when the 325 nm irradiation of a helium–cadmium laser (13 mW) is ceased. The afterglow spectrum of undoped SrAl2O4 is peaked at about 520 nm. From the peak temperature (321 K) of the broad thermoluminescence glow curve, the trap depth of trap levels in undoped SrAl2O4 is estimated to be 0.642 eV using Urbach’s formula. Based on first-principles density functional calculations, the bandstructures and densities of states are derived for oxygen-deficient SrAl2O4 and strontium-deficient SrAl2O4, respectively. Our results demonstrate that the green afterglow of undoped SrAl2O4 originates from the midgap states introduced by oxygen and strontium vacancies. The observation of green afterglow from undoped SrAl2O4 helps in gaining new insight in exploring the afterglow mechanisms of SrAl2O4-based afterglow materials.

Geometric, electronic properties of Au$_l$Pt$_m$ ($l$+$m$$\leqslant$10) clusters: A first-principles study

2021 ◽  
Author(s):  
Wei-Feng Xie ◽  
Hao-Ran Zhu ◽  
Shi-Hao Wei
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Inverse Design ◽  
Functional Theory ◽  
First Principles Study

The structural evolutions and electronic properties of Au$_l$Pt$_m$ ($l$+$m$$\leqslant$10) clusters are investigated by using the first$-$principles methods based on density functional theory (DFT). We use Inverse design of materials by...

Effect of dispersion on surface interactions of cobalt(ii) octaethylporphyrin monolayer on Au(111) and HOPG(0001) substrates: a comparative first principles study

2014 ◽  
Vol 16 (27) ◽  
pp. 14096-14107 ◽  
Author(s):  
Bhaskar Chilukuri ◽  
Ursula Mazur ◽  
K. W. Hipps
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Surface Interactions ◽  
Dispersion Interactions ◽  
Functional Theory ◽  
First Principles Study ◽  
Conductive Surfaces

Implication of dispersion interactions on geometric, adsorption and electronic properties of porphyrin monolayer on conductive surfaces using density functional theory.

scholarly journals Oxygen Vacancy Induced Magnetism in Anti-Perovskite Topological Dirac Semimetal Ba3SnO

2021 ◽  
Author(s):  
Javaria Batool ◽  
Syed Muhammad Alay-e-Abbas ◽  
Gustav Johansson ◽  
Waqas Zulfiqar ◽  
Muhammad Arsam Danish ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Electronic Properties ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Vacancy Defect ◽  
Functional Theory ◽  
Dirac Semimetal

The thermodynamic, structural, magnetic and electronic properties of pristine and intrinsic vacancy defect containing topological Dirac semimetal Ba3SnO are studied using first-principles density functional theory calculations. The thermodynamic stability of...

Sign in / Sign up

Export Citation Format

Share Document