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Journal articles on the topic 'Electronic Structure Calculations - Computational Methods'

Author: Grafiati

Published: 7 September 2023

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1

Wang, Lin-Wang. "Novel Computational Methods for Nanostructure Electronic Structure Calculations." Annual Review of Physical Chemistry 61, no. 1 (2010): 19–39. http://dx.doi.org/10.1146/annurev.physchem.012809.103344.

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2

Zhang, Xin, Jinwei Zhu, Zaiwen Wen, and Aihui Zhou. "Gradient Type Optimization Methods For Electronic Structure Calculations." SIAM Journal on Scientific Computing 36, no. 3 (2014): C265—C289. http://dx.doi.org/10.1137/130932934.

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3

Richie, D. A., P. von Allmen, K. Hess, and Richard M. Martin. "Electronic Structure Calculations Using An Adaptive Wavelet Basis." VLSI Design 8, no. 1-4 (1998): 159–63. http://dx.doi.org/10.1155/1998/62853.

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The use of a wavelet basis can lead to efficient methods for performing ab initio electronic structure calculations of inherently localized structures. In this work wavelets are used to construct an adaptive basis which is optimized dynamically throughout the calculation. The computational effort of such a method should scale linearly with the number of basis functions. The adaptive basis is tested for the case of bulk Si using only a local s-pseudopotential.

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Barettin, D., S. Madsen, B. Lassen, and M. Willatzen. "Computational Methods for Electromechanical Fields in Self-Assembled Quantum Dots." Communications in Computational Physics 11, no. 3 (2012): 797–830. http://dx.doi.org/10.4208/cicp.111110.110411a.

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AbstractA detailed comparison of continuum and valence force field strain calculations in quantum-dot structures is presented with particular emphasis to boundary conditions, their implementation in the finite-element method, and associated implications for electronic states. The first part of this work provides the equation framework for the elastic continuum model including piezoelectric effects in crystal structures as well as detailing the Keating model equations used in the atomistic valence force field calculations. Given the variety of possible structure shapes, a choice of pyramidal, s

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5

Zeng, Xiongzhi, Wei Hu, Xiao Zheng, Jin Zhao, Zhenyu Li, and Jinlong Yang. "Computational characterization of nanosystems." Chinese Journal of Chemical Physics 35, no. 1 (2022): 1–15. http://dx.doi.org/10.1063/1674-0068/cjcp2111233.

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Nanosystems play an important role in many applications. Due to their complexity, it is challenging to accurately characterize their structure and properties. An important means to reach such a goal is computational simulation, which is grounded on ab initio electronic structure calculations. Low scaling and accurate electronic-structure algorithms have been developed in recent years. Especially, the efficiency of hybrid density functional calculations for periodic systems has been significantly improved. With electronic structure information, simulation methods can be developed to directly ob

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Bligaard, Thomas, Martin P. Andersson, Karsten W. Jacobsen, Hans L. Skriver, Claus H. Christensen, and Jens K. Nørskov. "Electronic-Structure-Based Design of Ordered Alloys." MRS Bulletin 31, no. 12 (2006): 986–90. http://dx.doi.org/10.1557/mrs2006.225.

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AbstractWe describe some recent advances in the methodology of using electronic structure calculations for materials design. The methods have been developed for the design of ordered metallic alloys and metal alloy catalysts, but the considerations we present are relevant for the atomic-scale computational design of other materials as well. A central problem is how to treat the huge number of compounds that can be envisioned by varying the concentrations and the number of the elements involved. We discuss various strategies for approaching this problem and show how one strategy has led to the

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Pototschnig, Johann V., Kenneth G. Dyall, Lucas Visscher, and André Severo Pereira Gomes. "Electronic spectra of ytterbium fluoride from relativistic electronic structure calculations." Physical Chemistry Chemical Physics 23, no. 39 (2021): 22330–43. http://dx.doi.org/10.1039/d1cp03701c.

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Potential energy curves for the YbF obtained by relativistic electronic structure methods are presented. Due to the difficulties of describing this system separate computations for open and closed f-shells were necessary.

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Stöhr, Martin, Troy Van Voorhis, and Alexandre Tkatchenko. "Theory and practice of modeling van der Waals interactions in electronic-structure calculations." Chemical Society Reviews 48, no. 15 (2019): 4118–54. http://dx.doi.org/10.1039/c9cs00060g.

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Opening the black box of van der Waals-inclusive electronic structure calculations: a tutorial-style introduction to van der Waals dispersion interactions, state-of-the-art methods in computational modeling and complementary experimental techniques.

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9

Breczko, T., V. Barkaline, and J. Tamuliene. "INVESTIGATION OF GEOMETRIC AND ELECTRONIC STRUCTURES OF HEUSLER ALLOYS: CUBIC AND TETRAGONAL LATTICES." EPH - International Journal of Applied Science 6, no. 1 (2020): 1–5. http://dx.doi.org/10.53555/eijas.v6i1.102.

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Ni2MnGa and Co2MnGa compounds were investigated by using state-of-the-art computational ab-initio methods. The total energy calculations for the cubic and the tetrahedral structures, band structure together with suspensibility investigations were performed. The results of our investigations exhibited the dependence of magnetic properties of the compounds on their geometrical structure. The influence of Co and Ni on the magnetic properties of the compounds was disclosed, too.

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Fujiki, Ryo, Toru Matsui, Yasuteru Shigeta, Haruyuki Nakano, and Norio Yoshida. "Recent Developments of Computational Methods for pKa Prediction Based on Electronic Structure Theory with Solvation Models." J 4, no. 4 (2021): 849–64. http://dx.doi.org/10.3390/j4040058.

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The protonation/deprotonation reaction is one of the most fundamental processes in solutions and biological systems. Compounds with dissociative functional groups change their charge states by protonation/deprotonation. This change not only significantly alters the physical properties of a compound itself, but also has a profound effect on the surrounding molecules. In this paper, we review our recent developments of the methods for predicting the Ka, the equilibrium constant for protonation reactions or acid dissociation reactions. The pKa, which is a logarithm of Ka, is proportional to the r

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11

Bao, Gang, Guanghui Hu, and Di Liu. "Towards Translational Invariance of Total Energy with Finite Element Methods for Kohn-Sham Equation." Communications in Computational Physics 19, no. 1 (2016): 1–23. http://dx.doi.org/10.4208/cicp.190115.200715a.

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AbstractNumerical oscillation of the total energy can be observed when the Kohn- Sham equation is solved by real-space methods to simulate the translational move of an electronic system. Effectively remove or reduce the unphysical oscillation is crucial not only for the optimization of the geometry of the electronic structure, but also for the study of molecular dynamics. In this paper, we study such unphysical oscillation based on the numerical framework in [G. Bao, G. H. Hu, and D. Liu, An h-adaptive finite element solver for the calculations of the electronic structures, Journal of Computat

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12

Gao, Weiwei, Linda Hung, Serdar Ogut, and James R. Chelikowsky. "The stability, electronic structure, and optical absorption of boron-nitride diamondoids predicted with first-principles calculations." Physical Chemistry Chemical Physics 20, no. 28 (2018): 19188–94. http://dx.doi.org/10.1039/c8cp02377h.

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13

Perrella, Fulvio, Federico Coppola, Nadia Rega, and Alessio Petrone. "An Expedited Route to Optical and Electronic Properties at Finite Temperature via Unsupervised Learning." Molecules 28, no. 8 (2023): 3411. http://dx.doi.org/10.3390/molecules28083411.

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Electronic properties and absorption spectra are the grounds to investigate molecular electronic states and their interactions with the environment. Modeling and computations are required for the molecular understanding and design strategies of photo-active materials and sensors. However, the interpretation of such properties demands expensive computations and dealing with the interplay of electronic excited states with the conformational freedom of the chromophores in complex matrices (i.e., solvents, biomolecules, crystals) at finite temperature. Computational protocols combining time depend

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Gibbs, Josh, Alberto Otero de la Roza, Adam Johan Bergren, and Gino A. DiLabio. "Interpretation of molecular device transport calculations." Canadian Journal of Chemistry 94, no. 12 (2016): 1022–27. http://dx.doi.org/10.1139/cjc-2016-0279.

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The field of molecular electronics will benefit from rational design approaches based on a complete understanding of the electronic structure of molecule-based devices. However, many computational approaches that are used to study molecular-scale devices are based on methods that have deficiencies that must be understood in order for those methods to be useful to the modeling and experimental community. Density-functional theory based methods have some well-known pitfalls that limit their application to the study of electron transport in models of molecular junction devices. Some of the impact

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15

Beran, Gregory. "Modeling molecular crystals with fragment-based electronic structure techniques." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1616. http://dx.doi.org/10.1107/s2053273314083831.

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"A proper theoretical description of molecular crystal packing requires a uniformly high-quality treatment of the diverse intra- and intermolecular interactions. Fragment-based electronic structure methods enable the application of accurate electronic structure approaches to chemically interesting molecular crystals by decomposing the total crystal energy into the sum of many smaller ""fragment"" calculations. In this talk, we will discuss (1) the hybrid quantum/classical fragment based approach we have developed for molecular crystal problems, (2) state-of-the-art electronic structure approac

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Saßnick, Holger-Dietrich, and Caterina Cocchi. "Exploring cesium–tellurium phase space via high-throughput calculations beyond semi-local density-functional theory." Journal of Chemical Physics 156, no. 10 (2022): 104108. http://dx.doi.org/10.1063/5.0082710.

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Boosted by the relentless increase in available computational resources, high-throughput calculations based on first-principles methods have become a powerful tool to screen a huge range of materials. The backbone of these studies is well-structured and reproducible workflows efficiently returning the desired properties given chemical compositions and atomic arrangements as sole input. Herein, we present a new workflow designed to compute the stability and the electronic properties of crystalline materials from density-functional theory using the strongly constrained and appropriately normed a

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17

Slipokurov, V. A., P. P. Korniychuk, and A. V. Zinovchuk. "A method for fast calculating the electronic states in 2D quantum structures based on AIIIBV nitrides." Semiconductor Physics, Quantum Electronics and Optoelectronics 26, no. 2 (2023): 165–72. http://dx.doi.org/10.15407/spqeo26.02.165.

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The paper presents a method for fast calculating the electronic states in two-dimensional quantum structures based on AIIIBV nitrides. The method is based on the representation of electronic states in the form of a linear combination of bulk wave functions of materials, from which quantum structures are made. The parameters and criteria for the selection of bulk wave functions that provides fast convergence of the numerical procedures for calculating the eigenvalues of the quantum Hamiltonian have been considered. The results of the calculations have been given both for one polar InGaN/GaN qua

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18

Khoromskaia, Venera. "Black-Box Hartree–Fock Solver by Tensor Numerical Methods." Computational Methods in Applied Mathematics 14, no. 1 (2014): 89–111. http://dx.doi.org/10.1515/cmam-2013-0023.

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Abstract. The Hartree–Fock eigenvalue problem governed by the 3D integro-differential operator is the basic model in ab initio electronic structure calculations. Several years ago the idea to solve the Hartree–Fock equation by a fully 3D grid based numerical approach seemed to be a fantasy, and the tensor-structured methods did not exist. In fact, these methods evolved during the work on this challenging problem. In this paper, our recent results on the topic are outlined and the black-box Hartree–Fock solver by tensor numerical methods is presented. The approach is based on the rank-structure

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19

Drougas, Evangelos, and Agnie M. Kosmas. "Computational investigation of isomeric and conformeric structures of methyl iodoperoxide." Canadian Journal of Chemistry 83, no. 1 (2005): 9–15. http://dx.doi.org/10.1139/v04-156.

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Quantum mechanical electronic structure methods are employed to investigate the isomeric and conformeric stuctures of methyl iodoperoxide. Optimized geometries and harmonic vibrational frequencies are calculated at the MP2 level of theory using two types of basis sets, the 6-311G(d,p) for all atoms and the 6-311G(d,p) combined with the LANL2DZ relativistic ECP procedure for iodine. Refinement of the energetics has been accomplished by performing single-point CCSD(T) calculations. Five isomers were determined in total among which iodomethyl hydroperoxide (ICH2OOH) is found to be the lowest ener

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20

Anaya-Morales, A., and F. Delgado. "Enquiring Electronic Structure Using Quantum Computers: Hands on Qiskit." Journal of Physics: Conference Series 2448, no. 1 (2023): 012014. http://dx.doi.org/10.1088/1742-6596/2448/1/012014.

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Abstract Solving the electronic structure for multi-electronic systems is a hard problem. Even for small atoms and molecules, approximations have to be made in order to solve numerically the Schrödinger equation. Although different methods have been developed to take into account electron correlations, their computational cost reduces their feasibility. Quantum simulation provides an alternative to traditional computational methods for enquiring the electronic structure of molecules. Specifically, the Variational Quantum Eigensolver (VQE) algorithm provides a hybrid quantum-classical algorithm

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21

Epifanovsky, Evgeny, Michael Wormit, Tomasz Kuś, et al. "New implementation of high-level correlated methods using a general block tensor library for high-performance electronic structure calculations." Journal of Computational Chemistry 34, no. 26 (2013): 2293–309. http://dx.doi.org/10.1002/jcc.23377.

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22

Albaitai, Asmaa, and Saifaldeen M. Abdalhadi. "Modelling technique trend (interatomic potential) to study the mineral surfaces: Review." Samarra Journal of Pure and Applied Science 2, no. 3 (2021): 62–73. http://dx.doi.org/10.54153/sjpas.2020.v2i3.99.

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Computational chemistry is another branch of chemistry that can be used to model the material which is based on the mathematical methods and combined that with the theories of the quantum mechanics. However, in this filed there are two different techniques or categories, classical interatomic potential and the electronic structure methodology. The aim of this paper is to describe how can modelling the structures and energetics of surface and interface processes of minerals surface, using the classical atomistic simulation methods. We will illustrate the types of potentials and some of Codes (G

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23

Raja, G., K. Saravanan, and S. Sivakumar. "Molecular and Electronic Structure of 1-Naphtol : Ab Initio Molecular Orbital and Density Functional Study." Applied Mechanics and Materials 110-116 (October 2011): 1862–69. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1862.

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The molecular vibrations of 1-Naphtol were investigated in polycrystalline sample, at room temperature, by FT- IR and FT-Raman spectroscopy. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of 1-Naphtol . On the basis of B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations, a xnormal mode analysis was performed to assign the various fundamental frequencies according to the total energy distribution (TED). The vibrational spectra were interpreted, with the aid of normal coordinate

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24

Muchall, Heidi M., Nick H. Werstiuk, Jiangong Ma, Thomas T. Tidwell, and Kuangsen Sung. "Conformational behavior and electronic structure of silylketenes studied with quantum chemical calculations and photoelectron spectroscopy." Canadian Journal of Chemistry 75, no. 12 (1997): 1851–61. http://dx.doi.org/10.1139/v97-618.

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The He(I) photoelectron spectra of silylketenes (Me3Si)2C=C=O (1), Me5Si2CH=C=O (2), Me2Si(CH=C=O)2 (3), MeSi(CH=C=O)3 (4), (SiMe2CH=C=O)2 (5), and (CH2SiMe2CH=C=O)2 (6) have been recorded and their structures and orbital energies have been calculated by ab initio methods. Orbital energies for disilanes 2 and 5 are strongly dependent on a Si-Si-C-C torsional angle due to σ–π orbital interaction. Comparisons between experimental and simulated spectra show that 2 and 5 prefer conformations in which the Si—Si bond and ketene group(s) are approximately orthogonal (113° and 111°, respectively). Sil

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Kirchner-Hall, Nicole E., Wayne Zhao, Yihuang Xiong, Iurii Timrov, and Ismaila Dabo. "Extensive Benchmarking of DFT+U Calculations for Predicting Band Gaps." Applied Sciences 11, no. 5 (2021): 2395. http://dx.doi.org/10.3390/app11052395.

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Accurate computational predictions of band gaps are of practical importance to the modeling and development of semiconductor technologies, such as (opto)electronic devices and photoelectrochemical cells. Among available electronic-structure methods, density-functional theory (DFT) with the Hubbard U correction (DFT+U) applied to band edge states is a computationally tractable approach to improve the accuracy of band gap predictions beyond that of DFT calculations based on (semi)local functionals. At variance with DFT approximations, which are not intended to describe optical band gaps and othe

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Malcherek, Thomas, Markus Borowski, and Anne Bosenick. "Structure and phase transitions of CaTaOAlO4." Journal of Applied Crystallography 37, no. 1 (2004): 117–22. http://dx.doi.org/10.1107/s002188980302689x.

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The structure of CaTaOAlO4(CTAO) has been determined using X-ray powder diffraction and density functional methods in combination with27Al MAS NMR spectroscopy. A structural phase transition occurs near room temperature in CTAO as indicated by heat-capacity measurements, lattice strain data and infrared spectroscopy. Rietveld analysis of the powder diffraction data does not indicate deviation from monoclinic symmetryC2/c. But the observed quadrupolar coupling of the Al atom is reproduced by the electronic structure calculations only in a structure with space-group symmetryP21/n, distinguished

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Paolone, Annalisa, and Sergio Brutti. "Comparison of the Performances of Different Computational Methods to Calculate the Electrochemical Stability of Selected Ionic Liquids." Materials 14, no. 12 (2021): 3221. http://dx.doi.org/10.3390/ma14123221.

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The electrochemical stability windows (ESW) of selected ionic liquids have been calculated by comparing different computational approaches previously suggested in the literature. The molecular systems under study are based on di-alkyl imidazolium and tetra-alkyl ammonium cations coupled with two different imide anions (namely, bis-fluorosulfonyl imide and bis-trifluoromethyl sulfonyl imide), for which an experimental investigation of the ESW is available. Thermodynamic oxidation and reduction potentials have here been estimated by different models based on calculations either on single ions or

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Stefaniu, Amalia, Valeria Gabriela Savoiu, Irina Lupescu, and Olga Iulian. "Computational study on 3D structure of L-aspartic acid and L-glutamic acid: molecular descriptors and properties." Ovidius University Annals of Chemistry 27, no. 1 (2016): 48–52. http://dx.doi.org/10.1515/auoc-2016-0012.

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Abstract The aim of this work is to provide a comprehensive and complex analysis of molecular descriptors and properties of two similar amino acids, L-Aspartic acid and L-Glutamic acid, using a software tool for calculations and properties predictions. As amino acids are model compounds for predicting the physical-chemical properties and behavior of biological, larger molecules as peptides or proteins, researches were focused on providing accurate mechanical calculations using: molecular/mechanical methods. Our study aims to initiate a linear scaling approach, by dividing a large system into s

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Mihm, Tina N., Tobias Schäfer, Sai Kumar Ramadugu, Laura Weiler, Andreas Grüneis, and James J. Shepherd. "A shortcut to the thermodynamic limit for quantum many-body calculations of metals." Nature Computational Science 1, no. 12 (2021): 801–8. http://dx.doi.org/10.1038/s43588-021-00165-1.

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AbstractComputationally efficient and accurate quantum mechanical approximations to solve the many-electron Schrödinger equation are crucial for computational materials science. Methods such as coupled cluster theory show potential for widespread adoption if computational cost bottlenecks can be removed. For example, extremely dense k-point grids are required to model long-range electronic correlation effects, particularly for metals. Although these grids can be made more effective by averaging calculations over an offset (or twist angle), the resultant cost in time for coupled cluster theory

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Redfern, Simon A. T. "Advances in computer modelling of mineral properties." Mineralogical Magazine 59, no. 397 (1995): 585–87. http://dx.doi.org/10.1180/minmag.1995.059.397.01.

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The following six papers were presented at a meeting, held in September 1994, which reviewed some of the recent advances in the application of computational methods to mineralogy. Talks covered the developing and challenging field of ab initio quantum mechanical computations as well as new applications and insights afforded by the use and refinement of the more established methods of empirical simulation and modelling. The former attempt to solve Schrdinger's equation for the material in question, and in doing so determine the energy surface and electronic structure. The latter use parameteriz

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Rodrigues, Edson Silvio Batista, Isaac Yves Lopes de Macêdo, Larissa Lesley da Silva Lima, et al. "Electrochemical Characterization of Central Action Tricyclic Drugs by Voltammetric Techniques and Density Functional Theory Calculations." Pharmaceuticals 12, no. 3 (2019): 116. http://dx.doi.org/10.3390/ph12030116.

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This work details the study of the redox behavior of the drugs cyclobenzaprine (CBP), amitriptyline (AMP) and nortriptyline (NOR) through voltammetric methods and computational chemistry. Results obtained in this study show that the amine moiety of each compound is more likely to undergo oxidation at 1a at Ep1a ≈ 0.69, 0.79, 0.93 V (vs. Ag/AgCl/KClsat) for CBP, AMP and NOR, respectively. Moreover, CBP presented a second peak, 2a at Ep2a ≈ 0.98 V (vs. Ag/AgCl/KClsat) at pH 7.0. Furthermore, the electronic structure calculation results corroborate the electrochemical assays regarding the HOMO en

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WIJESEKERA, NIMAL, GUOGANG FENG, and THOMAS L. BECK. "MULTISCALE ALGORITHMS FOR EIGENVALUE PROBLEMS." Journal of Theoretical and Computational Chemistry 02, no. 04 (2003): 553–61. http://dx.doi.org/10.1142/s0219633603000665.

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Iterative multiscale methods for electronic structure calculations offer several advantages for large-scale problems. Here we examine a nonlinear full approximation scheme (FAS) multigrid method for solving fixed potential and self-consistent eigenvalue problems. In principle, the expensive orthogonalization and Ritz projection operations can be moved to coarse levels, thus substantially reducing the overall computational expense. Results of the nonlinear multiscale approach are presented for simple fixed potential problems and for self-consistent pseudopotential calculations on large molecule

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Harbury, Henry K., and Wolfgang Porod. "Parallel Computation for Electronic Waves in Quantum Corrals." VLSI Design 6, no. 1-4 (1998): 47–51. http://dx.doi.org/10.1155/1998/15645.

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Recent scanning tunneling microscopy (STM) studies on the (111) faces of noble metals have directly imaged electronic surface-confined states and dramatic standing-wave patterns have been observed 1,2]. We solve for the local density of electronic states in these “leaky” quantum corral confinement structures using a coherent elastic scattering theory. We seek solutions of the two-dimensional Schrödinger equation compatible with non-reflecting boundary conditions which asymptotically satisfy the Sommerfeld radiation condition [11,14]. The large matrices generated by the discretization of realis

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Morgante, Pierpaolo, and Roberto Peverati. "Comparison of the Performance of Density Functional Methods for the Description of Spin States and Binding Energies of Porphyrins." Molecules 28, no. 8 (2023): 3487. http://dx.doi.org/10.3390/molecules28083487.

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This work analyzes the performance of 250 electronic structure theory methods (including 240 density functional approximations) for the description of spin states and the binding properties of iron, manganese, and cobalt porphyrins. The assessment employs the Por21 database of high-level computational data (CASPT2 reference energies taken from the literature). Results show that current approximations fail to achieve the “chemical accuracy” target of 1.0 kcal/mol by a long margin. The best-performing methods achieve a mean unsigned error (MUE) <15.0 kcal/mol, but the errors are at least twic

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Ibrir, Miloud. "Structural, electronic and thermoelectric properties of the intermetallic materials based on Mg2X (X= Si, Ge, Sn): DFT calculations." International Journal of Energetica 2, no. 2 (2017): 25. http://dx.doi.org/10.47238/ijeca.v2i2.44.

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The scope of this work is the investigation of the physical properties of chalcopyrite materials using ab-initio methods in order to simulate a new structure of thin-films photovoltaic cells with high conversion efficiency. In the first framework, we obtained the results of calculations based on Density Functional Theory (DFT) using the full-potential linearized augmented plane wave method (FP-LAPW) as involved in the WIEN2K computational package. For the exchange-correlation potential, the local density approximation (LDA) was used to calculate the lattice parameters, Bulk modulus and its fir

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Pike, Nicholas A., Ruth Pachter, Alan D. Martinez, and Gary Cook. "Computational analysis of the optical response of ZnSe with d-orbital defects." Journal of Physics: Condensed Matter 34, no. 20 (2022): 205402. http://dx.doi.org/10.1088/1361-648x/ac594a.

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Abstract The doping of wide band-gap semiconducting ZnSe by transition metal (TM) atoms finds applications from mid-infrared lasing, sensing, photoelectrochemical cells, to nonlinear optics. Yet understanding the response of these materials at the atomic and electronic level is lacking, particularly in comparing a range of TM dopants, which were studied primarily by phenomenological crystal-field theory. In this work, to investigate bulk ZnSe singly doped with first-row TM atoms, specifically Ti through Cu, we applied a first-principles approach and crystal-field theory to explain the origin o

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Corà, Furio, Luis Gómez-Hortigüela, and C. Richard A. Catlow. "Aerobic oxidation of hydrocarbons in Mn-doped aluminophosphates: a computational perspective to understand mechanism and selectivity." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, no. 2143 (2012): 2053–69. http://dx.doi.org/10.1098/rspa.2012.0046.

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We discuss the mechanism and energetics for the aerobic oxidation of hydrocarbons catalysed by Mn-doped nanoporous aluminophosphates with the AFI structure (Mn-APO-5), obtained computationally using electronic structure techniques. Calculations have been performed employing hybrid exchange density functional theory methods under periodic boundary conditions. The active sites of the catalyst are tetrahedral Mn ions isomorphously replacing Al in the microporous crystalline framework of the AlPO host. Since all Al sites in AFI are symmetry equivalent, all Mn dopants are in an identical chemical a

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ONDOCKO, STEFAN, JOZEF SVETLIK, TOMAS STEJSKAL, MICHAL SASALA, and LUKAS HRIVNIAK. "COMPARISON SELECTED NUMERICAL METHODS FOR THE CALCULATION INVERSE KINEMATICS OF NON-STANDARD MODULAR ROBOTIC ARM CONSISTING OF UNIQUE ROTATIONAL MODULES." MM Science Journal 2021, no. 2 (2021): 4468–73. http://dx.doi.org/10.17973/mmsj.2021_6_2021042.

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The paper compares the most commonly used numerical methods of solving a set of nonlinear equations, especially in terms of computational speed. The methods are applied to a set of nonlinear equations that describe the forward kinematics of a non-standard robotic arm. This arm is an open-loop kinematics chain, composed of special rotary modules. A non-standard feature of the modules is the unlimited rotation around their own axis. This robotic arm consists of six such modules and, thus, has six degrees of freedom. Computations of this nonlinear set of equations are also called inverse kinemati

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Al-Sehemi, Abdullah G., Tarek M. El-Gogary, Karl Peter Wolschann, and Gottfried Koehler. "Structure and Stability of Chemically Modified DNA Bases: Quantum Chemical Calculations on 16 Isomers of Diphosphocytosine." ISRN Physical Chemistry 2013 (February 25, 2013): 1–10. http://dx.doi.org/10.1155/2013/146401.

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We studied for the first time 16 tautomers/rotamers of diphosphocytosine by four computational methods. Some of these tautomers/rotamers are isoenergetic although they have different structures. High-level electron correlation MP2 and MP4(SDQ) ab initio methods and density functional methods employing a B3LYP and the new M06-2X functional were used to study the structure and relative stability of 16 tautomers/rotamers of diphosphocytosine. The dienol tautomers of diphosphocytosine are shown to be much more stable than the keto-enol and diketo forms. The tautomers/rotamers stability could be ra

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Chan, Kwai S., Yi Ming Pan, and Yi Der Lee. "First-Principles Computation of Transition-Metal Diffusion Mobility." Defect and Diffusion Forum 266 (September 2007): 73–82. http://dx.doi.org/10.4028/www.scientific.net/ddf.266.73.

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First–principle computational methods have been utilized to compute the diffusion mobility of Mo, Cr, Fe, and W. A local density-based full-potential linearized augmented plane wave (FLAPW) code, named WIEN2K, was utilized to compute the electronic structure and total energy of an n-atom supercell with atom positions designed to simulate the desired diffusion processes. The computational procedure involves the calculations of the energy for vacancy formation and the energy barrier for solute migration in the host metal. First-principles computational results of the energy of vacancy formation,

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Sanna, Nico, and Maurizio Benfatto. "Benchmarking Plane Waves Quantum Mechanical Calculations of Iron(II) Tris(2,2′-bipyridine) Complex by X-ray Absorption Spectroscopy." Condensed Matter 7, no. 1 (2022): 16. http://dx.doi.org/10.3390/condmat7010016.

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In this work, we used, for the first time, a computational Self-Consistent Field procedure based on plane waves to describe the low and high spin conformational states of the complex [Fe(bpy)3]2+. The results obtained in the study of the minimum energy structures of this complex, a prototype of a wide class of compounds called Spin Cross Over, show how the plane wave calculations are in line with the most recent studies based on gaussian basis set functions and, above all, reproduce within acceptable errors the experimental spectra of X-ray absorption near-edge structure spectroscopy (XANES).

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Abgaryan, Karine, Ilya Mutigullin, and Dmitriy Bazhanov. "Multiscale Computational Model of Nitride Semiconductor Nanostructures." Advanced Materials Research 560-561 (August 2012): 1133–37. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.1133.

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Theoretical multiscale model of nitride semiconductor nanostructure is proposed. The model combines various computational methods such as density functional theory, molecular dynamics and kinetic Monte Carlo. As a first step of implementation of proposed approach ab initio calculations of structural and electronic properties of two different structures InN/Si and AlN/AlGaN/GaN heterostructures were carried out. In particular, the influence of oxygen on InN/Si adhesion energy was studied. AlN, GaN, AlxGa1-xN (x=0.33) spontaneous and piezoelectric polarizations as well as sheet carrier concentra

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Male, Yusthinus T., Djulia Onggo, Muhamad A. Martoprawiro, and Ismunandar Ismunandar. "THEORETICAL STUDY OF THE [Fe(en)₂(NCS)₂] COMPLEX WITH REPARAMETERIZED DENSITY FUNCTIONALS." Indonesian Journal of Chemistry 9, no. 3 (2010): 432–36. http://dx.doi.org/10.22146/ijc.21511.

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Quantum chemical studies have been carried out on the Fe(en)2(NCS)2 (en = ethylenediamine) complex both in low and high spin states (S = 0 and S = 2) using hybrid exchange-correlation functional (B3LYP) and non-hybrid method (BLYP). Calculations were performed in vacuum and in methanol to study the effect of cis-trans geometry on the structure and energy difference between low-spin (LS) and high-spin (HS) states of iron (II) complexes. Full geometry optimizations of the complexes show that hybrid method consistently gives higher energy difference between LS and HS states than the nonhybrid met

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Harper, Angela F., Matthew L. Evans, James P. Darby, et al. "Ab initio Structure Prediction Methods for Battery Materials : A review of recent computational efforts to predict the atomic level structure and bonding in materials for rechargeable batteries." Johnson Matthey Technology Review 64, no. 2 (2020): 103–18. http://dx.doi.org/10.1595/205651320x15742491027978.

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Portable electronic devices, electric vehicles and stationary energy storage applications, which encourage carbon-neutral energy alternatives, are driving demand for batteries that have concurrently higher energy densities, faster charging rates, safer operation and lower prices. These demands can no longer be met by incrementally improving existing technologies but require the discovery of new materials with exceptional properties. Experimental materials discovery is both expensive and time consuming: before the efficacy of a new battery material can be assessed, its synthesis and stability m

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Xu, Chao, and Dong Chen. "Electronic Structures of the High-Pressure hcp and bcc Phases of Al: A Computer Aided Design and Simulation." Applied Mechanics and Materials 556-562 (May 2014): 523–26. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.523.

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Thestate-of-the-artplane-wave methods combined with ultra-soft pseudo-potentials were employed to study the crystal and electronic structures (density of state, band structure) of aluminum in its hcp and bcc structures. In our computation we used the PBE functional, which predicts lattice constants very close to the experimental data. The calculations reveal that the whole valence band of Al is dominated by the 3s and 3p states while the conduction band is mainly contributed by the 3p band. The band structure shows that bcc-Al has a 0eV gap, which reflects its metallic character. The dispersio

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Quintas-Sánchez, Ernesto, and Richard Dawes. "Spectroscopy and Scattering Studies Using Interpolated Ab Initio Potentials." Annual Review of Physical Chemistry 72, no. 1 (2021): 399–421. http://dx.doi.org/10.1146/annurev-physchem-090519-051837.

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The Born–Oppenheimer potential energy surface (PES) has come a long way since its introduction in the 1920s, both conceptually and in predictive power for practical applications. Nevertheless, nearly 100 years later—despite astonishing advances in computational power—the state-of-the-art first-principles prediction of observables related to spectroscopy and scattering dynamics is surprisingly limited. For example, the water dimer, (H2O)2, with only six nuclei and 20 electrons, still presents a formidable challenge for full-dimensional variational calculations of bound states and is considered

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Dahanayake, Jayangika N., Chandana Kasireddy, Jonathan M. Ellis, et al. "Evaluating electronic structure methods for accurate calculation of 19 F chemical shifts in fluorinated amino acids." Journal of Computational Chemistry 38, no. 30 (2017): 2605–17. http://dx.doi.org/10.1002/jcc.24919.

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Grant, Ian, and Harry Quiney. "GRASP: The Future?" Atoms 10, no. 4 (2022): 108. http://dx.doi.org/10.3390/atoms10040108.

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The theoretical foundations of relativistic electronic structure theory within quantum electrodynamics (QED) and the computational basis of the atomic structure code GRASP are briefly surveyed. A class of four-component basis set is introduced, which we denote the CKG-spinor set, that enforces the charge-conjugation symmetry of the Dirac equation. This formalism has been implemented using the Gaussian function technology that is routinely used in computational quantum chemistry, including in our relativistic molecular structure code, BERTHA. We demonstrate that, unlike the kinetically matched

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Tanuma, Yuri, Toru Maekawa, and Chris Ewels. "Methodological Investigation for Hydrogen Addition to Small Cage Carbon Fullerenes." Crystals 11, no. 11 (2021): 1334. http://dx.doi.org/10.3390/cryst11111334.

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Hydrogenated small fullerenes (Cn, n < 60) are of interest as potential astrochemical species, and as intermediates in hydrogen-catalysed fullerene growth. However, the computational identification of key stable species is difficult due to the vast configurationally space of structures. In this study, we explored routes to predict stable hydrogenated small fullerenes. We showed that neither local fullerene geometry nor local electronic structure analysis was able to correctly predict subsequent low-energy hydrogenation sites, and sequential stable addition searches also sometimes failed to

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SRIWICHITKAMOL, KRIENGSAK, SONGWUT SURAMITR, POTJAMAN POOLMEE, and SUPA HANNONGBUA. "STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY." Journal of Theoretical and Computational Chemistry 05, no. 03 (2006): 595–608. http://dx.doi.org/10.1142/s0219633606002520.

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The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexy

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