A Molecular Full-Potential LMTO Calculation for Copper Clusters

1997 ◽  
Vol 11 (05) ◽  
pp. 161-169 ◽  
Author(s):  
Radhika Prosad Datta ◽  
Amitava Banerjea ◽  
Abhijit Mookerjee ◽  
A. K. Bhattacharyya
Keyword(s):  
Simulated Annealing ◽  
Binding Energy ◽  
Electronic Properties ◽  
Density Of States ◽  
Cluster Size ◽  
Binding Energies ◽  
Full Potential ◽  
Copper Clusters ◽  
Total Energies ◽  
Homo Lumo

We study the electronic properties of small (10–20 atoms) copper clusters using the newly-developed molecular full-potential linearized muffin-tin orbital two-centre-fit (TCF) method of Methfessel and van Schilfgaarde. The geometric structures of the clusters had earlier been determined by us through simulated annealing using the Equivalent Crystal Theory to compute total energies. We report the variation of the binding energy, as obtained from the TCF calculations, with cluster size and compare these to the binding energies determined, for the same structures, from the ECT. We also show the variation of the HOMO-LUMO gap with cluster size, and the pseudo-density of states for select cluster sizes.

Ab Initio Investigation of Structural and Electronic Properties of ErPb3 in AB3 Structure

2016 ◽  
Vol 28 ◽  
pp. 39-42 ◽  
Author(s):  
Shubha Dubey ◽  
Gitanjali Pagare ◽  
Ekta Jain ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Total Energy ◽  
Electronic Properties ◽  
Density Of States ◽  
Experimental Results ◽  
Energy Calculation ◽  
Present Calculation ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Calculated Density

The structural properties and electronic properties of the intermetallic compound ErPb3 which crystallize in AuCu3 type structure (AB3) are studied by means of first principles total energy calculation using full potential linearized plane wave method (FP-LAPW) within the generalized gradient approximation of Perdew, Burke and Ernzrhof (PBE) and local spin density approximation (LSDA) for the exchange correlation functional and including spin magnetic calculation. The total energy is computed as a function of volume and fitted to the Birch-Murnaghan equation of state. The ground state properties of this compound such as equilibrium lattice parameter (a0), bulk modulus (B), and its pressure derivative (B’) are calculated and compared with the available experimental results. We find good agreement with the other theoretical and experimental results. For the compounds, the values of lattice constants obtained by PBE-GGA overestimates and by LSDA underestimates the available experimental values for the same, which verifies the reliability of the present calculation. The value obtained for the bulk modulus is 50.63 GPa. The analysis of electronic properties is achieved by the calculation of the band structures and the density of states in both the spin up and spin down modes, which show a metallic character of ErPB3 due to zero band gap. The values of calculated density of states are found to be 0.36 eV/states and 11.46 eV/states in spin-up and spin-down mode respectively. The calculated magnetic moment (μm) of ErPb3 is 2.06.

FIRST-PRINCIPLES STUDY OF STRUCTURES AND ELECTRONIC PROPERTIES FOR NITRIDE-DOPED ALUMINUM CLUSTERS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2380-2385 ◽  
Author(s):  
BAOLIN WANG ◽  
DALING SHI ◽  
XIAOSHUANG CHEN ◽  
GUANGHOU WANG ◽  
JIJUN ZHAO
Keyword(s):  
Genetic Algorithm ◽  
Electronic Properties ◽  
Atomic Structure ◽  
Ground State ◽  
First Principles ◽  
Cluster Size ◽  
Aluminum Clusters ◽  
Structural And Electronic Properties ◽  
Ground State Structures ◽  
Homo Lumo

By using Gaussian98 package at BPW91 6-31g(d,p) level combined a genetic algorithm (GA) simulation, we have studied the lowest energy structural and electronic properties of the Al n N ( n =2-13) clusters. The ground-state structures, the charge transfers from Al to N site, HOMO-LUMO gap and the covalent, ionic and metallic nature with cluster size and atomic structure are investigated. Al 7 N , Al 9 N and Al 12 N cluster is found particularly stable among the Al n N clusters.

STABILITY ANALYSIS OF SMALL COPPER NANOCLUSTERS

2012 ◽  
Vol 11 (01) ◽  
pp. 1250006
Author(s):  
PRABODH SAHAI SAXENA ◽  
PANKAJ SRIVASTAVA ◽  
ASHWANI Kr. SHRIVASTAVA
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Local Density ◽  
Binding Energies ◽  
Density Approximation ◽  
Copper Nanoclusters ◽  
Functional Theory ◽  
Total Energies ◽  
Homo Lumo ◽  
Atom Bond

We have investigated the lowest-energy structures and electronic properties of the Cu n(n = 2–10) nanoclusters based on density functional theory (DFT) in local density approximation. The total energies, binding energies per atom, bond lengths, HOMO-LUMO gaps and ionization potentials have been calculated. The results are compared well with other theoretical and available experimental results.

scholarly journals Giant gate-tunable bandgap renormalization and excitonic effects in a 2D semiconductor

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw2347 ◽  
Author(s):  
Zhizhan Qiu ◽  
Maxim Trushin ◽  
Hanyan Fang ◽  
Ivan Verzhbitskiy ◽  
Shiyuan Gao ◽  
...  
Keyword(s):  
Binding Energy ◽  
Single Layer ◽  
Scanning Tunneling Spectroscopy ◽  
Binding Energies ◽  
Exciton Binding Energy ◽  
Scanning Tunneling ◽  
Full Potential ◽  
2D Semiconductors ◽  
Wide Range ◽  
Excitonic Effects

Understanding the remarkable excitonic effects and controlling the exciton binding energies in two-dimensional (2D) semiconductors are crucial in unlocking their full potential for use in future photonic and optoelectronic devices. Here, we demonstrate large excitonic effects and gate-tunable exciton binding energies in single-layer rhenium diselenide (ReSe2) on a back-gated graphene device. We used scanning tunneling spectroscopy and differential reflectance spectroscopy to measure the quasiparticle electronic and optical bandgap of single-layer ReSe2, respectively, yielding a large exciton binding energy of 520 meV. Further, we achieved continuous tuning of the electronic bandgap and exciton binding energy of monolayer ReSe2 by hundreds of milli–electron volts through electrostatic gating, attributed to tunable Coulomb interactions arising from the gate-controlled free carriers in graphene. Our findings open a new avenue for controlling the bandgap renormalization and exciton binding energies in 2D semiconductors for a wide range of technological applications.

THEORETICAL STUDY OF HIGHLY DOPED HETEROFULLERENES EVOLVED FROM THE D6h SYMMETRY C36 CAGE

2013 ◽  
Vol 12 (07) ◽  
pp. 1350067
Author(s):  
F. NADERI ◽  
M. R. MOMENI ◽  
F. A. SHAKIB
Keyword(s):  
Charge Transfer ◽  
Hydrogen Storage ◽  
Electronic Properties ◽  
Vibrational Frequency ◽  
Theoretical Study ◽  
Binding Energies ◽  
Triplet States ◽  
Electronic Excitations ◽  
Singlet And Triplet States ◽  
Homo Lumo

The structural stabilities and electronic properties of singlet and triplet states C 24X12 heterofullerenes where X = B , Al , C , Si , N , and P are probed at the B3LYP/6-31+G* level of theory. Vibrational frequency calculations show that all of the systems are true minima. The calculated binding energies of heterofullerenes show C 24 B 12 and C 24 N 12 as the most stable heterofullerenes by 6.10 eV/atom and 5.63 eV/atom, respectively. While B , Al , N and P doping increase the conductivity of fullerene through decreasing its HOMO–LUMO gap, doping Si enhance its stability against electronic excitations via increasing the HOMO–LUMO gap. High charge transfer on the surfaces of our stable heterofullerenes, especially C 24 Al 12 followed by C 24 Si 12 and C 24 P 12, provokes further investigations on their possible application for hydrogen storage.

Lowest Energy Structures and Electronic Properties of Small Molybdenum Clusters

2005 ◽  
Vol 494 ◽  
pp. 79-82 ◽  
Author(s):  
V. Koteski ◽  
Bozidar Cekić ◽  
N. Novaković ◽  
J. Belošević-Čavor
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
First Principles ◽  
Cluster Size ◽  
Density Functional ◽  
Theoretical Data ◽  
Binding Energies ◽  
Functional Theory ◽  
Average Bond

The structural and geometric properties of small Mo clusters are studied by means of first principles density functional theory (DFT) calculations with planewaves and pseudopotentials. The lowest energy structures of Mon (n=2-6) clusters are determined. The evolution of electronic properties with increasing cluster size is discussed. The geometric structure, average bond lengths, and binding energies of the lowest energy isomers are reported and the results are compared with the available experimental and theoretical data.

scholarly journals First-Principles Studies on the Structural and Electronic Properties of As Clusters

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1596 ◽  
Author(s):  
Jialin Yan ◽  
Jingjing Xia ◽  
Qinfang Zhang ◽  
Binwen Zhang ◽  
Baolin Wang
Keyword(s):  
Genetic Algorithm ◽  
Density Functional Theory ◽  
Binding Energy ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Size Dependent ◽  
Structural And Electronic Properties ◽  
Homo Lumo

Based on the genetic algorithm (GA) incorporated with density functional theory (DFT) calculations, the structural and electronic properties of neutral and charged arsenic clusters Asn (n = 2–24) are investigated. The size-dependent physical properties of neutral clusters, such as the binding energy, HOMO-LUMO gap, and second difference of cluster energies, are discussed. The supercluster structures based on the As8 unit and As2 bridge are found to be dominant for the larger cluster Asn (n ≥ 8). Furthermore, the possible geometric structures of As28, As38, and As180 are predicted based on the growth pattern.

First-principles study of the stability of graphene and adsorption of halogen atoms (F, Cl and Br) on hydrogen passivated graphene

2014 ◽  
Vol 28 (21) ◽  
pp. 1450141 ◽  
Author(s):  
D. B. Karki ◽  
N. P. Adhikari
Keyword(s):  
Binding Energy ◽  
Carbon Atom ◽  
First Principles ◽  
Cluster Size ◽  
Energy Gap ◽  
Lumo Energy ◽  
Halogen Atoms ◽  
The Stability ◽  
Homo Lumo ◽  
Graphene Cluster

First-principles calculations based on Hartree–Fock (HF) and density functional theory (DFT) levels of approximation have been carried out in order to study the stability of graphene clusters as a function of number of carbon atoms (N). The variation of calculated binding energy per carbon atom with corresponding number of carbon atoms (N) in graphene cluster almost saturates after the cluster size consisting of 96 carbon atoms, with binding energy per carbon atom 8.24 eV/atom. Adsorption of halogen atoms, ( F , Cl and Br ), on hydrogen passivated graphene ( H -graphene) was also studied systematically through first-principles DFT calculations by taking five different H -graphene clusters. The calculations showed that the most stable adsorption site for halogen adatoms on H -graphene being T site with binding energy 2.41 eV ( F ), 1.48 eV ( Cl ) and 1.19 eV ( Br ) on the H -graphene cluster consisting 96 carbon atoms. Moreover, on increasing the size of H -graphene cluster, the binding energy of halogen adatoms found to be increasing. The distances of adatom from the nearest carbon atom of H -graphene sheet were 1.47 Å ( F ), 2.71 Å ( Cl ) and 3.01 Å ( Br ), however, the adatom heights from the H -graphene basal plane were 2.22 Å ( F ), 2.90 Å ( Cl ), and 3.19 Å ( Br ). The bonding of halogen adatoms on H -graphene were through the charge transfer; 0.30 | e | ( F ), 0.37 | e | ( Cl ) and 0.19 | e | ( Br ), from H -graphene to adatoms and includes the negligible local distortion in the underlying planner H -graphene. Charge redistribution upon adsorption induces significant dipole moments 2.16 D ( F ), 4.81 D ( Cl ) and 3.08 D ( Br ) on H -graphene. The calculated HOMO–LUMO energy gap of adatom- H -graphene and H -graphene does not differ significantly up to the cluster size N = 30, however, beyond N = 30 adsorption of halogen adatoms significantly opens the HOMO–LUMO energy gap on H -graphene and the opening of HOMO–LUMO energy gap also saturates from N = 96. Correlation of computed HOMO–LUMO energy gap and corresponding binding energy of adatom- H -graphene systems have been also studied.

Electronic Properties and Formation Mechanism of Metallo-Carbohedrenes

1994 ◽  
Vol 349 ◽  
Author(s):  
Yoshiyuki Kawazoe ◽  
Bing-Lin Gu ◽  
Mark van Schilfgaarde ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno
Keyword(s):  
Electronic Properties ◽  
Density Of States ◽  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Mulliken Population ◽  
Calculated Density ◽  
Single Cage ◽  
Atomic Orbitals ◽  
Local Density Functional

ABSTRACTWe have calculated the structure and electronic properties of several metallo-carbohedrenes within the local density-functional approximation, using both methods of a linear combination of atomic orbitals and full-potential muffin-tin orbitals. The calculated density of states and Mulliken population of double cage Ti14C21 and triple cage Ti18C29 are quite similar to that of single cage Ti8C12. There is no additional cohesion in multicage structure, which may explain why there is not a strong tendency to form larger, multi-cage structures. A new stable structure for Ti8C12 is also proposed and structures Ti10C12+x (x=1, 2, 3, 4, 5) have also been discussed.

Determination of the Ground State Geometries of Copper Clusters by Simulated Annealing

1997 ◽  
Vol 11 (19) ◽  
pp. 2333-2341
Author(s):  
Amitava Banerjea ◽  
Radhika Prosad Datta ◽  
Abhijit Mookerjee ◽  
A. K. Bhattacharyya
Keyword(s):  
Simulated Annealing ◽  
Cluster Size ◽  
Size Range ◽  
Monte Carlo Algorithm ◽  
Equilibrium Geometry ◽  
Copper Clusters ◽  
Atom Clusters ◽  
Metropolis Monte Carlo ◽  
Semi Empirical

We determine the lowest energy structures of small (10–20 atoms) copper clusters. The semi-empirical Equivalent Crystal Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedral structures. The 13-atom cluster is an icosahedron and the 19-atom one a double-icosahedron. The other sizes show structures related to these. The 10- and 11-atom clusters, however, show somewhat different structures. We report the variation of binding energy, as obtained from ECT, with cluster size.

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