FLAME: A library of atomistic modeling environments

Amsler, Maximilian; Rostami, Samare; Tahmasbi, Hossein; Khajehpasha, Ehsan Rahmatizad; Faraji, Somayeh; Rasoulkhani, Robabe; Ghasemi, S. Alireza

doi:10.1016/j.cpc.2020.107415

Cited by 31 publications

(21 citation statements)

References 70 publications

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“…For each cluster size, we run MH at least 10 times with different random starting structures, i.e., different points on the energy landscape, to scan the PES thoroughly. All of the local minima structures obtained from these MH runs for each size are carefully refined by environment descriptors 42 implemented in the FLAME code 43 to conveniently identify and remove potential duplicates. This way, we find all of the structures which have been reported before by Guvelioglu et al 21 In addition, we also discover several new low-energy structures for each cluster size.…”

Section: Methodsmentioning

confidence: 99%

IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters

et al. 2021

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IR spectra of cationic copper clusters Cu n + ( n = 4–7) complexed with hydrogen molecules are recorded via IR multiple-photon dissociation (IRMPD) spectroscopy. To this end, the copper clusters are generated via laser ablation and reacted with H 2 and D 2 in a flow-tube-type reaction channel. The complexes formed are irradiated using IR light provided by the free-electron laser for intracavity experiments (FELICE). The spectra are interpreted by making use of isotope-induced shifts of the vibrational bands and by comparing them to density functional theory calculated spectra for candidate structures. The structural candidates have been obtained from global sampling with the minima hopping method, and spectra are calculated at the semilocal (PBE) and hybrid (PBE0) functional level. The highest-quality spectra have been recorded for [5Cu, 2H/2D] + , and we find that the semilocal functional provides better agreement for the lowest-energy isomers. The interaction of hydrogen with the copper clusters strongly depends on their size. Binding energies are largest for Cu 5 + , which goes hand in hand with the observed predominantly dissociative adsorption. Due to smaller binding energies for dissociated H 2 and D 2 for Cu 4 + , also a significant amount of molecular adsorption is observed as to be expected according to the Evans–Polanyi principle. This is confirmed by transition-state calculations for Cu 4 + and Cu 5 + , which show that hydrogen dissociation is not hindered by an endothermic reaction barrier for Cu 5 + and by a slightly endothermic barrier for Cu 4 + . For Cu 6 + and Cu 7 + , it was difficult to draw clear conclusions because the IR spectra could not be unambiguously assigned to structures.

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Section: Methodsmentioning

confidence: 99%

IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters

et al. 2021

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“…The MH method [33][34][35]64,65] was used for an efficient scanning of the potential energy surface to find low-energy structures. The density functional theory (DFT) calculations for total-energy and relaxations were carried out using the VIENNA AB-INITIO SIMULATION PACKAGE (VASP) [66,67]; B and C atoms were described by the built-in projector augmented-wave (PAW) potentials [68] with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional [69].…”

Section: Structure Prediction and Dft Calculationsmentioning

confidence: 99%

High-temperature conventional superconductivity in the boron-carbon system: Material trends

et al. 2020

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In this paper, we probe the possibility of high-temperature conventional superconductivity in the boron-carbon system, using ab initio screening. A database of 320 metastable structures with fixed composition (50%/50%) is generated with the minima hopping method, and characterized with electronic and vibrational descriptors. Full electron-phonon calculations on 16 representative structures allow us to identify general trends in T c across and within the four families in the energy landscape, and to construct an approximate T c predictor, based on transparently interpretable and easily computable electronic and vibrational descriptors. Based on these, we estimate that around 10% of all metallic structures should exhibit T c 's above 30 K. This paper is a first step toward ab initio design of new high-T c superconductors.

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“…states has been recognized already some time ago, and for simple empirical force fields different solutions have been proposed [28][29][30][31] . In the context of ML potentials the first method that has been proposed to address this problem is the charge equilibration via neural network technique (CENT) [32][33][34] . In this method, a charge equilibration 28 scheme is applied, which allows for a global redistribution of the charge over the full system to minimize a charge-dependent total energy expression.…”

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confidence: 99%

A fourth-generation high-dimensional neural network potential with accurate electrostatics including non-local charge transfer

et al. 2021

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Machine learning potentials have become an important tool for atomistic simulations in many fields, from chemistry via molecular biology to materials science. Most of the established methods, however, rely on local properties and are thus unable to take global changes in the electronic structure into account, which result from long-range charge transfer or different charge states. In this work we overcome this limitation by introducing a fourth-generation high-dimensional neural network potential that combines a charge equilibration scheme employing environment-dependent atomic electronegativities with accurate atomic energies. The method, which is able to correctly describe global charge distributions in arbitrary systems, yields much improved energies and substantially extends the applicability of modern machine learning potentials. This is demonstrated for a series of systems representing typical scenarios in chemistry and materials science that are incorrectly described by current methods, while the fourth-generation neural network potential is in excellent agreement with electronic structure calculations.

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FLAME: A library of atomistic modeling environments

Cited by 31 publications

References 70 publications

IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters

IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters

High-temperature conventional superconductivity in the boron-carbon system: Material trends

A fourth-generation high-dimensional neural network potential with accurate electrostatics including non-local charge transfer

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FLAME: A library of atomistic modeling environments

Cited by 31 publications

References 70 publications

IR Spectroscopic Characterization of H2 Adsorption on Cationic Cun+ (n = 4–7) Clusters

IR Spectroscopic Characterization of H2 Adsorption on Cationic Cun+ (n = 4–7) Clusters

High-temperature conventional superconductivity in the boron-carbon system: Material trends

A fourth-generation high-dimensional neural network potential with accurate electrostatics including non-local charge transfer

Contact Info

Product

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IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters

IR Spectroscopic Characterization of H₂ Adsorption on Cationic Cu_n⁺ (n = 4–7) Clusters