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.

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.

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.

Transition metal Mo-doped boron clusters: A computational investigation

2014 ◽  
Vol 13 (05) ◽  
pp. 1450036 ◽  
Author(s):  
Run-Ning Zhao ◽  
Yanhong Yuan ◽  
Ju-Guang Han
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Natural Populations ◽  
Chemical Hardness ◽  
Functional Theory ◽  
Relative Stabilities ◽  
Boron Clusters ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Homo Lumo

Geometries associated with relative stabilities and energy gaps of the Mo -doped boron clusters have been investigated systematically by using density functional theory. The critical size of Mo -encapsulated B n structures emerges as n = 10, the evaluated relative stabilities in term of the calculated fragmentation energies reveal that the MoB 6 has enhanced stabilities over their neighboring clusters. Furthermore, the calculated polarities of the MoB n reveal that the hypercoordinated planar MoB 10 wheel is a weakened polar molecule and MoB 11 ring is a nonpolar molecule, and aromatic properties are discussed. Additionally, the MoB 10 cluster with smaller highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap is supposed to be stronger chemical activity and smaller chemical hardness. Moreover, the recorded natural populations show that the charges transfer from boron framework to Mo atom. It should be pointed out that the remarkable charge-transfer features of MoB n clusters are distinctly similar to those of transitional metal (TM)-doped Si n clusters; growth-pattern of the TMBn depends on the doped TM impurity.

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.

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.

Synthesis and characterization of oligo-4-[(pyridin-3-ylimino)methyl]phenol

2007 ◽  
Vol 61 (3) ◽  
Author(s):  
İ. Kaya ◽  
S. Çulhaoğlu ◽  
D. Şenol
Keyword(s):  
Molecular Orbital ◽  
Thermal Analyses ◽  
Size Exclusion ◽  
Degradation Temperature ◽  
Highest Occupied Molecular Orbital ◽  
N2 Atmosphere ◽  
Exclusion Chromatography ◽  
N Doping ◽  
Lowest Unoccupied Molecular Orbital ◽  
Optimum Reaction

AbstractThe oxidative polycondensation of 4-[(pyridin-3-ylimino)methyl]phenol (4-PIMP) with O2, H2O2, and NaOCl was studied in an aqueous alkaline medium between 50°C and 90°C. Oligo-4-[(pyridin-3-ylimino)methyl]phenol (O-4-PIMP) prepared was characterized by 1H-NMR, 13C-NMR, FT-IR, UV-VIS, size-exclusion chromatography, and elemental and thermal analyses techniques. At the optimum reaction conditions, the yield of O-4-PIMP was 18.9%, 39.4%, and 46.8% using H2O2, O2, and NaOCl oxidant, respectively. According to the TG analysis, the initial degradation temperature of O-4-PIMP was 218°C, which was by 50°C higher than that of 4-PIMP. Thermal analyses of 4-PIMP and O-4-PIMP were carried out in N2 atmosphere at 15–1000°C. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and electrochemical energy gaps of 4-PIMP and O-4-PIMP were determined from the onset potentials for n-doping and p-doping, respectively. Also, optical band gaps of 4-PIMP and O-4-PIMP were determined according to UV-VIS measurements.

scholarly journals QTAIM investigation of bis(pyrazol-1-yl)methane derivative and its Zn(II) complexes (ZnLX2, X=Cl, Br or I)

2015 ◽  
Vol 80 (8) ◽  
pp. 997-1008 ◽  
Author(s):  
Maryam Dehestani ◽  
Leila Zeidabadinejad
Keyword(s):  
Molecular Orbital ◽  
Critical Points ◽  
Structural Parameters ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Theory Approach ◽  
Topological Parameters ◽  
Molecular Orbital Energy ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

Topological analyses of the electron density using the quantum theory of atoms in molecules (QTAIM) have been carried out at the B3PW91/6-31g (d) theoretical level, on bis(pyrazol-1-yl)methanes derivatives 9-(4-(di (1H-pyrazol-1-yl)-methyl)phenyl)-9H-carbazole (L) and its zinc(II) complexes: ZnLCl2 (1), ZnLBr2 (2) and ZnLI2 (3). The topological parameters derived from Bader theory were also analyzed; these are characteristics of Zn-bond critical points and also of ring critical points. The calculated structural parameters are the frontier molecular orbital energies highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), hardness (?), softness (S), the absolute electronegativity (?), the electrophilicity index (?) and the fractions of electrons transferred (?N) from ZnLX2 complexes to L. The numerous correlations and dependencies between energy terms of the Symmetry Adapted Perturbation Theory approach (SAPT), geometrical, topological and energetic parameters were detected and described.

Sign in / Sign up

Export Citation Format

Share Document