scholarly journals Electronic Properties of Triangle Molybdenum Disulfide (MoS2) Clusters with Different Sizes and Edges

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1157
Author(s):  
Songsong Wang ◽  
Changliang Han ◽  
Liuqi Ye ◽  
Guiling Zhang ◽  
Yangyang Hu ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Edge States ◽  
Frontier Orbitals ◽  
Edge Structure ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The electronic structures and transition properties of three types of triangle MoS2 clusters, A (Mo edge passivated with two S atoms), B (Mo edge passivated with one S atom), and C (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S3p at the edge and hybrid states of Mo4d and S3p covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS2 clusters, their absorption spectra show unique characteristics along with the edge structure and size.

Theoretical studies on lindqvist polyoxometalates [M6O19]n−(M = Mo, W, n=2; M = V, Nb, Ta, n=8) and derivatives: Electronic structures, stability and bonding

2017 ◽  
Vol 16 (06) ◽  
pp. 1750054 ◽  
Author(s):  
Xiao-Fang Su ◽  
Bo Zhu ◽  
Cai-Xia Wu ◽  
Li-Kai Yan ◽  
Zhong-Min Su
Keyword(s):  
Charge Density ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Density Functional ◽  
Geometrical Structure ◽  
Energy Gap ◽  
Lumo Energy ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The geometrical and electronic structures of [M6O[Formula: see text]][Formula: see text] (M [Formula: see text] Mo, W, [Formula: see text]; M [Formula: see text] V, Nb, Ta, [Formula: see text]) and their derivatives were investigated by using density functional theory methods. The results indicate that the geometrical structure of [V6O[Formula: see text]][Formula: see text] is not different from other Lindqvist-type anions. The energy gap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) (HOMO[Formula: see text]LUMO energy gap) of [V6O[Formula: see text]][Formula: see text] is smaller than those of same charge anions, [Nb6O[Formula: see text]][Formula: see text] and [Ta6O[Formula: see text]][Formula: see text]. In addition, the charge density [Formula: see text] of [V6O[Formula: see text]][Formula: see text] is larger when compared with those of other studied clusters. The investigation on the derivatives shows that the valence of V atom (V[Formula: see text] or V[Formula: see text]) and the methoxy ligand influence the HOMO[Formula: see text]LUMO energy gap and the charge density [Formula: see text] of the studied clusters.

Structures and electronic properties of the transition metal-adsorbed B36 clusters

2020 ◽  
Vol 34 (34) ◽  
pp. 2050387
Author(s):  
Zhi Li ◽  
Zhen Zhao ◽  
Qi Wang ◽  
Tao-Tao Shao
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Molecular Orbital ◽  
Structural Stability ◽  
Metal Doping ◽  
Boron Clusters ◽  
Kinetic Activity ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

Metal doping is considered as an effective method to stabilize the structures and optimize the properties of boron clusters. The structures and electronic properties of the [Formula: see text] clusters have been calculated at the Perdew–Burkle–Ernzerhof (PBE) level. The results reveal that the Cu atoms for the [Formula: see text] clusters unexpectedly enter the [Formula: see text] clusters. Ti, V, Co, Ni, Zr, Hf, Ta and W can obviously increase the structural stability of pristine [Formula: see text] clusters. The Ti, Cr, Fe, Ni and Zn; Y, Ru and Ag; Lu, Ta, Ir and Au-adsorbed [Formula: see text] clusters display higher kinetic activity than other [Formula: see text] clusters. The d orbital electrons of the TM atoms will significantly affect the distributions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) states of pristine [Formula: see text] clusters. All the TM–B bonds of the [Formula: see text] clusters display covalent characters.

DFTB Calculation of Si Atomic Chains’ Structures and Electronic Properties

2016 ◽  
Vol 848 ◽  
pp. 494-497
Author(s):  
Xiu Min Xu ◽  
Li Jun Wu ◽  
Lin Zhang
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Tight Binding ◽  
Functional Theory ◽  
Symmetrical Distribution ◽  
Highest Occupied Molecular Orbital ◽  
Atomic Chains ◽  
Lowest Unoccupied Molecular Orbital

In this paper, structures and electronic properties of atomic chains with 5 to 20 silicon atoms and different atomic distances (d = 1.652 ~ 2.752Å) were calculated by the tight-binding method based on density functional theory. The results showed that the majority of the silicon atomic chains were symmetrical structures. When the number of silicon atoms was small, the silicon atomic chains were linear, when the silicon atomic chains had seven or more silicon atoms zigzag structures appeared. With the increase of the distance between atoms, atomic chains were gathering. When the number of silicon atoms was between 10 and 20, the charges on the silicon atoms appeared as a symmetrical distribution. With the increase of the number of atoms, the energy of silicon atomic chains decreased gradually. As the distance between atoms and atomic number changed, HOMO (highest occupied molecular orbital electrons) -LUMO (lowest unoccupied molecular orbital electrons) energy gap changed as well.

ELECTRONIC PROPERTIES OF HETEROFULLERENES C59X (X=Si, O AND Be)

2000 ◽  
Vol 14 (01) ◽  
pp. 23-29 ◽  
Author(s):  
JING LU ◽  
XINWEI ZHANG ◽  
XIANGENG ZHAO
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Local Density ◽  
Electron Affinities ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Local Density Functional ◽  
Silicon Oxygen

It has been found in earlier calculations that by replacing one C atom with one N atom, one electron is doped in the lowest unoccupied molecular orbital (LUMO) of C60 while by replacing with one B atom, one hole is doped in the highest occupied molecular orbital (HOMO) of C60. In this paper, we have performed discrete-variational local density functional calculations on single silicon, oxygen and beryllium-substituted heterofullerenes. No carrier is doped in the C60-derived orbitals upon Si substitution except for the reduced LUMO–HOMO gap. Two electrons are doped in the LUMO of C60 upon O substitution and instead, two holes are doped in the HOMO of C60 upon Be substitution. Ionization potentials and electron affinities can be altered dramatically by substitution and in general, C60 becomes more reactive upon substitution.

Electronic State Calculation of Manganese Dioxide and Manganese-Molybdenum Oxide for Dimensionally Stable Anode

2007 ◽  
Vol 26-28 ◽  
pp. 969-972 ◽  
Author(s):  
B.S. Kim ◽  
Dong Yoon Lee ◽  
Hee Woong Lee ◽  
Won Sub Chung
Keyword(s):  
Manganese Dioxide ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Cluster Model ◽  
Manganese Atom ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Energy Band Gap ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The effect of molybdenum substitution in electronic structures of manganese dioxide has been calculated by the DV-Xα molecular orbital method. The molybdenum atom substituted for manganese atom located in center-sited of (Mn15O56)-52 cluster model. By the molybdenum substitution the energy band gap between the highest occupied molecular orbital (HOMO) of valence band and the lowest unoccupied molecular orbital (LUMO) was decreased, also the interaction of Mn-3d and O-2p was weakened but that of Mo-4d and O-2p was intensified. Both bonds of (Mn15O56)-52 and (Mn14MoO56)-52 was composed of not only ionic but also partially covalent.

scholarly journals Geometry, Energy, and Some Electronic Properties of Carbon Polyprismanes: Ab Initio and Tight-Binding Study

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Konstantin P. Katin ◽  
Stanislav A. Shostachenko ◽  
Alina I. Avkhadieva ◽  
Mikhail M. Maslov
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Tight Binding ◽  
Binding Energies ◽  
Effective Length ◽  
Binding Model ◽  
Highest Occupied Molecular Orbital ◽  
Semiconducting Properties ◽  
Lowest Unoccupied Molecular Orbital

We report geometry, energy, and some electronic properties of [n,4]- and [n,5]prismanes (polyprismanes): a special type of carbon nanotubes constructed from dehydrogenated cycloalkane C4- and C5-rings, respectively. Binding energies, interatomic bonds, and the energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) have been calculated using density functional approach and nonorthogonal tight-binding model for the systems up to thirty layers. It is found that polyprismanes become more thermodynamically stable as their effective length increases. Moreover, they may possess semiconducting properties in the bulk limit.

Geometrical and electronic properties of PdWSin (n=10–20) semiconductor materials

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Rui Chen ◽  
Fan Lin ◽  
Hua Jin ◽  
Run-Ning Zhao
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Silicon Clusters ◽  
Functional Methods ◽  
Highest Occupied Molecular Orbital ◽  
Doped Silicon ◽  
Lowest Unoccupied Molecular Orbital ◽  
Silicon Frame ◽  
Homo Lumo

Abstract Geometries and electronic properties of PdWSin (n=10–20) clusters are investigated by density functional methods. According to our calculated results, it is obvious that tungsten (W)-encapsulated silicon frame determines the final PdWSin (n=10–20) forms because W and silicon (Si) interactions are stronger than palladium (Pd)-Si interactions. The electronic charges are transferred from the Si frame to W firstly and Pd finally, which is completely different from the homoatomic transition metal (TM)2-doped silicon clusters. The calculated highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps exhibit that PdWSi12 has the biggest HOMO-LUMO gap.

Purple Photoluminescence from Banana-Shaped Molecules 1,3-Phenylene bis(4-methoxybenzylideneamine)

2010 ◽  
Vol 428-429 ◽  
pp. 182-185 ◽  
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai
Keyword(s):  
Optical Absorption ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Energy Levels ◽  
Tight Binding ◽  
Photoluminescence Spectra ◽  
Lone Pairs ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Ultraviolet Photons

The optical absorption and photoluminescence spectra of banana-shaped molecules 1,3-phenylene bis(4-methoxybenzylideneamine) have been investigated with an ultraviolet-visible spectrometers and a spectrofluorometer, respectively. The optical characterizations indicate that the banana-shaped molecules exhibit strong absorptions in a broad range of 260-370 nm and that they can give off strong purple photoluminescence when excited by ultraviolet photons. Using Hückel tight-binding program, we have calculated the electronic structures of the banana-shaped molecules. In light of the calculated electronic structures, the origin of the purple photoluminescence is discussed, and our results have demonstrated that not only the lowest unoccupied molecular orbital and the highest occupied molecular orbital but also the localized energy levels of the lone pairs are responsible for the recorded purple photoluminescence.

scholarly journals Photoconductivity of Low-Bandgap Polymer and Polymer: Fullerene Bulk Heterojunction Studied by Constant Photocurrent Method

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
V. V. Malov ◽  
A. R. Tameev ◽  
S. V. Novikov ◽  
M. V. Khenkin ◽  
A. G. Kazanskii ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Bulk Heterojunction ◽  
Inorganic Materials ◽  
Fullerene Derivative ◽  
Approximation Procedure ◽  
Photoelectric Properties ◽  
Highest Occupied Molecular Orbital ◽  
Donor Acceptor ◽  
Lowest Unoccupied Molecular Orbital ◽  
Doped Polymers

AbstractOptical and photoelectric properties of modern photosensitive polymers are of great interest due to their prospects for photovoltaic applications. In particular, an investigation of absorption and photoconductivity edge of these materials could provide valuable information. For these purpose we applied the constant photocurrent method which has proved its efficiency for inorganic materials. PCDTBT and PTB7 polymers were used as objects for the study as well as their blends with a fullerene derivative PC71BM. The measurements by constant photocurrent method (CPM) show that formation of bulk heterojunction (BHJ) in the blends increases photoconductivity and results in a redshift of the photocurrent edge in the doped polymers compared with that in the neat polymers. Obtained from CPM data, spectral dependences of absorption coefficient were approximated using Gaussian distribution of density-of-states within HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) bands. The approximation procedure allowed us to evaluate rather optical than electrical bandgaps for the studied materials. Moreover, spectra of polymer:PC71BM blends were fitted well by the sum of two Gaussian peaks which reveal both the transitions within the polymer and the transitions involving charge transfer states at the donor-acceptor interface in the BHJ.

scholarly journals Estudo do comportamento óptico-estrutural do LiNbO3

Cerâmica ◽  
2003 ◽  
Vol 49 (309) ◽  
pp. 36-39 ◽  
Author(s):  
C. D. Pinheiro ◽  
V. Bouquet ◽  
F. M. Pontes ◽  
E. R. Leite ◽  
E. Longo
Keyword(s):  
Molecular Orbital ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

Realizou-se um estudo teórico-experimental sobre as estruturas cristalina e amorfa de niobato de lítio, para verificar a influência dos defeitos sobre as propriedades ópticas desse semicondutor. Filmes finos cristalinos de LiNbO3 (c-LN) e amorfo (a-LN) foram preparados pelo método dos precursores poliméricos, sendo caracterizados por difração de raios X e microscopia de força atômica. As propriedades ópticas foram estudadas por UV-Visível e espectroscopia Raman. Em particular, o filme amorfo apresentou luminescência, cuja posição do pico varia de acordo com o comprimento de onda de excitação. A diferença de energia entre os níveis HOMO (Highest Occupied Molecular Orbital) e LUMO (Lowest Unoccupied Molecular Orbital) revela que o gap de banda da fase cristalina é maior que aquele exibido pela fase amorfa, em acordo com os dados experimentais de UV-visível. Observou-se o surgimento de novos níveis eletrônicos na região do gap de banda na estrutura amorfa, este fato pode explicar as propriedades ópticas particulares observadas sobre o filme amorfo.

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