scholarly journals First Principle Research on Ga Rich GaAs0.5P0.5(001) β2(4×2) and As(P) rich β2(2×4) Reconstruction Surfaces With and Without Cs Adsorption

2021 ◽  
Author(s):  
Siyi He ◽  
Mingzhu Yang ◽  
Shixin Pei
Keyword(s):  
Dipole Moments ◽  
Mulliken Charge ◽  
First Principle ◽  
Surface Work ◽  
Exothermic Process ◽  
Charge Analysis ◽  
Average Variation ◽  
Topmost Layer ◽  
Work Functions ◽  
Adsorption Energies

Abstract Based on first principle calculations, Ga rich and As(P) rich clean GaAs0.5P0.5(001) reconstruction surfaces and adsorbed surfaces with 0.125ML coverage of Cs at different sites are researched. Formation energy of Ga rich GaAs0.5P0.5(001) β2(4×2) reconstruction surface is smaller than that of As(P) rich one, and the work functions of Ga rich β 2 (4×2) and As(P) rich β2(2×4) surfaces are 4.657 eV and 5.187 eV, respectively. The adsorption energies of Cs adatoms on both surfaces are negative, showing that Cs adsorption is a stable exothermic process. The work functions of two surfaces both decrease after Cs adsorption, and the average variation of As(P) rich β2(2×4) surface is larger. Mulliken charge analysis shows that Cs adatoms transfer electrons to GaAsP substrate, resulting in Cs-GaAsP dioples which lower the work functions. When Cs atoms are located at D 2 of Ga rich surface and D 2 ' of As(P) rich surface, work function values of the two reconstruction surfaces reach the minimums, which are 2.834eV and 2.859eV, respectively. By calculating dipole moments, it can be found that Cs adatoms on the topmost layer form larger effective dipole moments with GaAsP substrate than the Cs atoms located in the trench.

scholarly journals A First-Principles Study of Gas Molecule Adsorption on Carbon-, Nitrogen-, and Oxygen-Doped Two-Dimensional Borophene

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xinmao Qin ◽  
Wanjun Yan ◽  
Dongxiang Li ◽  
Zhongzheng Zhang ◽  
Shaobo Chen
Keyword(s):  
First Principles ◽  
Adsorption Properties ◽  
Mulliken Charge ◽  
Valley Bottom ◽  
First Principles Study ◽  
Surface Work ◽  
Gas Molecule ◽  
Gas Molecules ◽  
Work Functions ◽  
Adsorption Energies

A first-principles study was performed to investigate the adsorption properties of gas molecules (CO, CO2, NO, and NO2) on carbon- (C-), nitrogen- (N-), and oxygen-doped (O) borophene. The adsorption energies, adsorption configurations, Mulliken charge population, surface work functions, and density of states (DOS) of the most stable doped borophene/gas-molecule configurations were calculated, and the interaction mechanisms between the gas molecules and the doped borophene were further analyzed. The results indicated that most of the gas molecules exhibited strong chemisorption at the VB site (the center of valley bottom B–B bond) of the doped borophene (compared to pristine borophene). Electronic property analysis of the C-doped borophene/CO2 and the NO2 adsorption system revealed that there were numerous charge transfers from the C-doped borophene to the CO2 and NO2 molecules. This indicated that C-doped borophene was an electron donor, and the CO2 and NO2 molecules served as electron acceptors. In contrast to variations in the adsorption energies, electronic properties, and surface work functions of the different gas, C-, N-, and O-doped borophene adsorption systems, we concluded that the C-, N-, and O-doped borophene materials will improve the sensitivity of CO, CO2, and NO2 molecule; this improvement of adsorption properties indicated that C-, N-, and O-doped borophene materials are excellent candidates for surface work functions transistor to detect gas molecules.

A FIRST-PRINCIPLE INVESTIGATION OF BORON- AND NITROGEN-DOPED HETEROFULLERENES

2011 ◽  
Vol 10 (01n02) ◽  
pp. 29-33 ◽  
Author(s):  
ISHA GARG ◽  
KEYA DHARAMVIR ◽  
V. K. JINDAL ◽  
HITESH SHARMA
Keyword(s):  
Chemical Properties ◽  
Structural Deformation ◽  
Mulliken Charge ◽  
First Principle ◽  
Nitrogen Doped ◽  
Device Applications ◽  
Charge Analysis ◽  
B Doping ◽  
A Charge ◽  
And Chemical Properties

A systematic study of structural, electronic and vibrational properties of boron- and nitrogen-doped heterofullerenes has been performed. N and B doping lead to the structural deformation, and the dopant has a tendency to occupy a single position in a pentagon and two positions in a hexagon which are not adjacent. B -substitution produces clusters of greater thermodynamic stability than N substitution. The C–N and C–B bond lengths lie in the range of 1.40–1.44 Å and 1.53–1.57 Å for hexagon–hexagon (6, 6) and 1.39–1.46 Å and 1.55–1.60 Å at pentagon–hexagon (5, 6) interfaces, respectively. The Mulliken charge analysis shows a charge transfer of -0.30 to -0.45 electrons from N to C atoms; B atom act as electron acceptors with charge gain ranging between -0.59 to -0.70 electrons. N - and B -doping in fullerene molecules present an interesting way to alter electronic and chemical properties of the C 60 molecule for useful device applications.

Small Al and Ga clusters trapped inside the Bucky-ball (C60) — A DFT study

2017 ◽  
Vol 31 (12) ◽  
pp. 1750092 ◽  
Author(s):  
Shobhna Dhiman ◽  
Ranjan Kumar ◽  
Keya Dharamvir
Keyword(s):  
Density Functional ◽  
Mulliken Charge ◽  
Dopant Atom ◽  
Generalized Gradient ◽  
Structural And Electronic Properties ◽  
Charge Analysis ◽  
Vertical Electron Affinity ◽  
Dopant Atoms ◽  
Ground State Structures ◽  
Homo Lumo

In the present paper, we have done a systematic study of structural and electronic properties of endohedrally doped C[Formula: see text] with Al and Ga atoms using density functional theory (DFT) with the help of Spanish initiative for electronic simulation with thousands of atoms (SIESTA) package in the generalized gradient approximation (GGA). The parameters calculated are binding energy/dopant atom, vertical ionization potential (VIP), vertical electron affinity (VEA), HOMO–LUMO gap and charge transfer. The stabilized ground state structures of Al[Formula: see text]@C[Formula: see text] ([Formula: see text]–10) and Ga[Formula: see text]@C[Formula: see text] ([Formula: see text]–10) show that a maximum of nine Al or Ga atoms can be encapsulated in C[Formula: see text] without distorting the cage significantly. Mulliken charge analysis shows an electron transfer from the metal dopant to the cage surface, except for Al[Formula: see text] ([Formula: see text]–10). The endohedral metal clusters adopt a more compact shape when inside C[Formula: see text], compared to its free-state configuration and its symmetry. The study of HOMO–LUMO gap reveals that the gap decreases with the increase in number of dopant atoms inside C[Formula: see text].

Density functional theory study of acrolein adsorption on graphyne

2015 ◽  
Vol 93 (11) ◽  
pp. 1261-1265
Author(s):  
A.R. Karami
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Adsorption Energy ◽  
Density Functional ◽  
Mulliken Charge ◽  
Density Functional Theory Study ◽  
Donor Molecule ◽  
Functional Theory ◽  
Charge Analysis ◽  
Semiconducting Property

We have used density functional theory to study the effect of acrolein adsorption on the electronic properties of graphyne. It is found that the acrolein molecule is physisorbed on graphyne sheets with small adsorption energy and large adsorption distance. Mulliken charge analysis indicates that charge is transferred from the acrolein molecule to the graphyne sheets. In the presence of this charge donor molecule, α- and β-graphyne with semimetallic properties and γ-graphyne with semiconducting property become n-type semiconductors. The sensitivity of the electronic properties of graphyne to the presence of acrolein indicates that graphyne sheets are appropriate materials to use as a sensor for acrolein detection.

scholarly journals Density functional theory calculations and Hirshfeld surface analysis of propyl-para-hydroxybenzoate (PHB) for optoelectronic application

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
V. Mohankumar ◽  
N. Karunagaran ◽  
M. Senthil Pandian ◽  
P. Ramasamy
Keyword(s):  
Charge Transfer ◽  
Surface Analysis ◽  
Density Functional ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Hirshfeld Surface Analysis ◽  
Frontier Molecular Orbital ◽  
Mulliken Charge ◽  
Charge Analysis ◽  
Orbital Analysis

AbstractThe geometries, electrostatic potential, Mulliken charge analysis, Natural Bond Orbital analysis and polarizabilities of propyl-para-hydroxybenzoate were calculated using B3LYP functional with 6-311++G(d,p) basis set. The calculated geometries are well matched with the experimental values. The Mullliken atomic charge analysis shows that the eventual charges are contained in the molecule. The NBO analysis explains the intramolecular charge transfer in the PHB molecule. The bonding features of the molecule were analyzed with the aid of Hirshfeld surface analysis. The frontier molecular orbital analysis showed the charge transfer obtained within the molecule. The calculated hyperpolarizability of the PHB molecule was 6.977E−30 esu and it was 8.9 times that of standard urea molecule.

scholarly journals First-Principle Study of Co-Adsorption Behavior of H2O and O2 on δ-Pu (100) Surface

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1098
Author(s):  
Guoliang Wang ◽  
Zhaoyang Zhao ◽  
Pengfei Zhai ◽  
Xudan Chen ◽  
Yefei Li
Keyword(s):  
Surface Layer ◽  
Energy Analysis ◽  
Co Adsorption ◽  
Adsorption Behavior ◽  
First Principle ◽  
Surface Corrosion ◽  
Preferential Adsorption ◽  
Density Analysis ◽  
Charge Analysis ◽  
Bader Charge Analysis

The surface corrosion of plutonium in air is mainly the result of the interaction with O2 and H2O in air. In this paper, the co-adsorption behavior of O2 and H2O on a δ-Pu (100) surface is studied by the first-principle method. Two different cases of preferential adsorption of H2O and O2 are considered, respectively. Bader charge analysis and adsorption energy analysis are carried out on all stable adsorption configurations, and the most stable adsorption configurations are found under the two conditions. The results of differential charge density analysis, the density of states analysis and Crystal Orbital Hamilton Populations (COHP) analysis show that the two molecules can promote each other’s adsorption behavior, which leads to the strength and stability of co-adsorption being far greater than that of single adsorption. In the co-adsorption configuration, O atoms preferentially interact with Pu atoms in the surface layer, and the essence is that the 2s and 2p orbitals of O overlap and hybridize with the 6p and 6d orbitals of Pu. H atoms mainly form O–H bonds with O atoms and hardly interact with Pu atoms on the surface layer.

A First-Principle Study of Fe-Doped Co3O4 on N-Doped Graphene as Electrocatalyst

2021 ◽  
Vol 897 ◽  
pp. 95-100
Author(s):  
Chun Ying Wang
Keyword(s):  
Catalytic Mechanism ◽  
Partial Density ◽  
First Principle ◽  
Fe Doping ◽  
Density Of State ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Doped Graphene ◽  
Adsorption Energies ◽  
Zinc Air Batteries

The metal-air batteries, especially the Zinc-air batteries, are great solutions to the growing energy crisis with excellent rechargeable capacity. ORR is the key electro-chemical reaction in Zinc-air batteries, and the development of the ORR efficiency is being studied extensively. The doping of transition metal in Co3O4, with the basement of N-doped graphene have been confirmed to have catalytic activity which can be comparable to Pt/C. Herein, the Fe-doped Co3O4 supported by N-doped graphene is constructed as the catalyst of ORR, and that without Fe doping is also constructed as comparison. Through first-principle calculation, it shows that the adsorption energies to O2 on the same site of each surface and on different sites on Fe-doped one. The partial density of state of the O2 adsorption system shows the effects of electron transfer and orbital hybridization on catalysis, which provide evidence to the catalytic mechanism with Fe doping. The energy changes of each step in ORR on catalyst with Fe doping and without Fe doping show the shortcomings of the simulation, including the spin of Fe atoms. Thus the study confirms that the adding of Fe contributes to the catalystic capability compared to the pure Co3O4.

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