Article
Materials Science, Multidisciplinary
Saro San, Yang Tong, Hongbin Bei, Boopathy Kombaiah, Yanwen Zhang, Wai-Yim Ching
Summary: A comparative study of high entropy alloys using ab initio calculations reveals intricate interdependence among electronic structure, interatomic bonding, partial charge distribution, and mechanical properties. The novel parameter of total bond order density (TBOD) is used to interpret the properties, with highest TBOD found in Cantor alloy NiFeCoCrMn. Experimental validation shows lattice distortions in NiFeCoCrMn and NiFeCoCrPd based on atomic radii variations. Modeling of Cu and Pd clustering in the supercell demonstrates lower total energy, consistent with observed enhancements in Cu and Pd-induced concentration wave in HEAs.
MATERIALS & DESIGN
(2021)
Article
Physics, Multidisciplinary
Sebastian Horvat, Borivoje Dakic
Summary: This study demonstrates a quantum advantage in acquiring and transmitting information encoded globally, showing a quadratic enhancement in information acquisition speed using quantum information carriers compared to their classical counterparts.
NEW JOURNAL OF PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
A. V. Zinovchuk, V. S. Slipokurov
Summary: This paper presents a modified empirical pseudopotential based method for calculating the electronic structure of InGaN/GaN quantum wells. The method describes the confining potential as a difference between the atomic potential of the constituent bulk material and a superposition of the potentials of the atoms forming the quantum well. By considering the atomistic formulation of the quantization problem, the method avoids approximations and includes the effects of random alloy fluctuations on the electronic states. Furthermore, the method maintains a high computational efficiency.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Chemistry, Physical
Zhikang Yuan, Wentao Hu, Dongli Yu
Summary: NaB13C2 is a new boron-rich boride carbide synthesized from sodium, exhibiting a reddish black metallic luster and a regular hexagonal prism shape under high temperature and pressure. It crystallizes into an orthorhombic structure and shows a wide band gap semiconductor characteristic.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Inorganic & Nuclear
Yong Tan, Limin Ma, Yishu Wang, Wei Zhou, Xiaolu Wang, Fu Guo
Summary: The structure stability, mechanical properties, and thermodynamic behaviors of Al4Si6La3 compound were investigated in a wide pressure range of 0-100 GPa using first-principles calculations based on density functional theory. The results showed that the compound was thermodynamically stable at 0 GPa but became unstable with increasing pressure. The compound exhibited ductile nature at pressures up to 100 GPa, and the Debye temperature and minimum thermal conductivity were improved with increasing pressure. The analysis of electronic structures revealed the formation of covalent bonds between Al-Si and La-Si in the compound, while Al-La formed antibonding states at different pressures.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Physics, Multidisciplinary
Keisuke Higashi, Mathias Winder, Jan Kunes, Atsushi Hariki
Summary: By studying the core-level spectra, the optimal model parameters for the ground state of NdNiO2 were determined, showing that self-doping from the Nd 5d states prevents the opening of a Mott-Hubbard gap. However, the current calculations for LaNiO2 cannot explain the difference in spectra compared to NdNiO2.
Article
Chemistry, Inorganic & Nuclear
Xian Wei, Qi Zhang, Zhongjie Cui, Dan Yang, Shiliang Mei, Wanlu Zhang, Haijiao Xie, Kehan Yu, Ruiqian Guo, Wei Wei
Summary: Understanding the electronic structure of doped InP quantum dots is crucial for optimizing the material for specific applications. This study combines experimental and computational approaches to investigate the doping mechanism and surface passivation of InP QDs. The results provide insights into the microscopic details of doped InP and offer the potential for precise control of guest ion stoichiometry for optimized electrical devices.
INORGANIC CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Jean-Baptiste Moree, Robinson Outerovitch, Bernard Amadon
Summary: In this study, ab initio calculations were performed to determine the effective interaction parameters for actinide dioxides, showing the importance of self-consistent values for aligning with experimental results. Additionally, considering the oxygen p bands as correlated was found to have an impact on the outcomes.
Article
Chemistry, Physical
Tomislav Begusic, Enrico Tapavicza, Jiri Vanicek
Summary: This study explores the applicability of the single-Hessian thawed Gaussian approximation for simulating the vibrational resolved electronic spectra of anharmonic systems. The method is shown to be more robust and accurate than the traditional harmonic approximation, especially in cases where the harmonic approximation breaks down.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Optics
Rebecka Sax, Alberto Boaron, Gianluca Boso, Simone Atzeni, Andrea Crespi, Fadri Grunenfelder, Davide Rusca, Aws Al-Saadi, Danilo Bronzi, Sebastian Kupijai, Hanjo Rhee, Roberto Osellame, Hugo Zbinden
Summary: Quantum key distribution (QKD) is a reliable method for generating secure secret keys at a distance, relying on the laws of quantum physics instead of computational complexity. To industrialize QKD, affordable and practical setups are needed, and the integration of photonic and electronic components is currently emphasized. This study presents an integrated QKD setup featuring a high-speed transmitter chip in silicon photonics and a low-loss receiver chip in aluminum borosilicate glass, achieving comparable performance to more complex setups based on discrete components.
PHOTONICS RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Jindou Ru, Rui Ma, Mingpan Wan, Quan Xie
Summary: This study investigates the formability, electronic structures, Debye temperatures, and mechanical properties of TiVCrTa multicomponent alloys with different crystal structures using first principles methods. The results show that these alloys exhibit good ductility and stability, and have different mechanical properties, electronic structures, and atomic bonding characteristics in different directions.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Maxwell Aifer, Sebastian Deffner
Summary: This article studies the energetically optimal implementation of quantum operations. By using the framework of quantum speed limits, we find the universally optimal solutions for single and N-qubit operations.
NEW JOURNAL OF PHYSICS
(2022)
Article
Chemistry, Physical
Zhaoyang Cheng, Zhixian Peng, Bolin Zhong, Huijun Liu, Zhihong Lu, Sicong Zhu, Jing Liu
Summary: The substitution behavior of Cu doped into Fe3Si and its effect on the electronic structure and mechanical properties of Fe3Si were investigated. It was found that the covalent bond was weakened after Cu doping, while the ionic bond strength was in the order of Fe11CuSi4(I) > Fe3Si > Fe11CuSi4(II) > Fe12Si3Cu. Cu atom preferred to substitute Fe atom, particularly Fe(I), but hardly substitute the Si atom. Cu doping decreased the antiphase boundary energy (ABPE) and increased the plasticity of Fe3Si alloy by the dominant influence of the reduced APBE and weakened covalent bonds.
Article
Physics, Multidisciplinary
Brij Mohan, Siddhartha Das, Arun Kumar Pati
Summary: This study determines the speed limits on the evolution of informational measures in quantum systems, such as von Neumann entropy, maximal information, and coherence. These limits provide crucial insights into the minimal time required for erasing quantum information, which is essential for future quantum computing devices.
NEW JOURNAL OF PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Robert Polly, Bianca Schacherl, Joerg Rothe, Tonya Vitova
Summary: Relativistic multiconfigurational all-electron ab initio calculations, including spin-orbit interaction, accurately reproduce experimental results for uranyl's 3d4f resonant 5f inelastic X-ray scattering (RIXS) map. The calculated data provide insights into the fine structure splitting of 4f orbitals induced by trans di-oxo bonds in uranyl, allowing for a clear understanding of energy differences between 5f and 4f orbitals. Ab initio calculations show the versatility of multiconfigurational protocols in studying RIXS maps of systems containing actinides.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Christoph Bannwarth, Todd J. Martinez
Summary: The article presents an approach to unify ab initio and semiempirical electronic structure code paths. By separating the wavefunction ansatz and the matrix representations of operators, the Hamiltonian can refer to either an ab initio or semiempirical treatment. The authors built a semiempirical integral library and interfaced it to the GPU-accelerated electronic structure code TeraChem. This approach enables the combination of semiempirical Hamiltonians with the full functionality of the ab initio electronic structure code.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Roger Jan Kutta, Johannes Grosskopf, Nils van Staalduinen, Antonia Seitz, Philipp Pracht, Stefan Breitenlechner, Christoph Bannwarth, Patrick Nuernberger, Thorsten Bach
Summary: In the presence of a chiral benzophenone catalyst, a racemic mixture of a chiral imidazolidine-2,4-dione can be converted into the same compound with high enantiomeric excess through photochemical deracemization. Mechanistic experiments revealed that the catalyst binds the two enantiomers through hydrogen bonding and facilitates hydrogen atom transfer to the photoexcited benzophenone. Quantum chemical calculations showed that the back hydrogen atom transfer occurs to the oxygen atom of the hydantoin radical. The results provide insights into a synthetically useful photochemical deracemization reaction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Benedikt Wolff, Zheng-Wang Qu, Stefan Grimme, Martin Oestreich
Summary: This study presents a method for the enantioselective reduction of simple carbenium ions using cyclohexadienes with a hydridic C-H bond at an asymmetrically substituted carbon atom. Chiral cyclohexadienes are used as dihydrogen surrogates for the transfer hydrogenation of alkenes (styrenes). The reaction mechanism involves the initiation by trityl cation and a delicate intermolecular capture of a carbenium-ion intermediate by the chiral hydride source, resulting in good enantiomeric ratios of the reduction products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Julia T. Kohn, Hong Li, Austin M. Evans, Jean-Luc Bredas, Stefan Grimme
Summary: 2D covalent organic frameworks (COFs) possess desirable mechanical and optoelectronic properties, but experimental structure determination remains challenging due to inseparable isomers and limited computational models. In this study, we go beyond the conventional description of COF building blocks and investigate the impact of different stacking and structural motifs on electronic properties. Using the SQM GFN-xTB method, we analyze the structural, energetic, electronic, and spectroscopic results of an imine-linked COF and compare them to experimental findings.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Stefan Grimme, Marcel Mueller, Andreas Hansen
Summary: This article describes a new tight-binding electronic structure Hamiltonian that achieves high accuracy and speedup in calculations using a deeply contracted valence double-zeta basis set. The method performs well for difficult systems and bonding situations, and can be used for machine learning applications or as a basis for accurate high-speed DFT methods.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Editorial Material
Chemistry, Multidisciplinary
Zahid Hussain, Yong-an Luo, Yile Wu, Zheng-wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Interest in main group chemistry related to the Haber-Bosch process is less studied compared to transition metal species. In this study, steric demands in (tBuO(2)CN)(2) hinder the initial interaction of B(C6F5)(3) with nitrogen, leading to the loss of methylpropene and CO2 and the formation of diazene (N2H2) borane adduct 1 and the analogous hydrazine (N2H4) adduct 2. These species react with basic phosphines to form anions of 3 and 5, which contain N2H and N2H3 fragments and serve as metal-free models of plausible intermediates in N-2 reduction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Daniel Kalle, Joshua Bahr, Tristan Johannes Keller, Julius B. Kleine Buening, Stefan Grimme, Markus Bursch, Stefan-Sven Jester, Sigurd Hoeger
Summary: The modular synthesis of nanoscale phenylene bicyclophanes with an intraannular orthogonal pillar is described in this study. The compounds were characterized by various analytical techniques, and their structures and conformations were further supported by quantum chemical calculations. It was found that the number of alkyl chains per molecule plays a crucial role in determining the structural stability of the assembled molecules on graphite. This study provides important insights into the assembly and characterization of nanomaterials.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
J. T. Kohn, N. Gildemeister, S. Grimme, D. Fazzi, A. Hansen
Summary: Designing organic semiconductors for practical applications requires understanding charge transfer mechanisms. This study used a semiempirical quantum mechanical method combined with a non-self-consistent density matrix tight-binding potential to evaluate charge transfer integrals. The results showed that the method consistently performs well for calculating coupling integrals with reasonable accuracy at low computational cost.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Hagen Neugebauer, Benedikt Badorf, Sebastian Ehlert, Andreas Hansen, Stefan Grimme
Summary: The semiempirical GFNn-xTB methods are extended with spin-polarization to efficiently screen different spin states of transition metal complexes. The new spGFNn-xTB methods overcome the limitation of properly distinguishing between high-spin and low-spin states. Performance evaluation on a benchmark set of 90 complexes shows that spGFNn-xTB methods yield the lowest mean absolute deviation (MAD) for spin state energy splittings.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Marcel Stahn, Sebastian Ehlert, Stefan Grimme
Summary: We have developed a new method, named CPCM-X, to accurately account for solvation effects in semiempirical quantum mechanics. This method combines the computationally efficient ddCOSMO model with established solvation models like COSMO-RS and SMD, and improves the accuracy of solvation free energies by up to 40% for large supramolecular association reactions. The proposed method is more accurate and more than 2 orders of magnitude faster than the current methods in the xtb program package.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Cyclopropenium cations with electron deficient substituents exhibit Lewis acidity despite the presence of π-electrons. The chloride and electron affinities are analyzed computationally and experimentally, respectively. These cations form traditional Lewis acid-base adducts with PPh3, while sterically hindered phosphines lead to frustrated Lewis pairs that participate in FLP additions. Depending on the basicity of the phosphine, addition to alkynes or alkyne deprotonation can occur. In both cases, new C-C bonds are formed, thus expanding the application of FLP chemistry to these delocalized π-cations.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Christoph Plett, Abylay Katbashev, Sebastian Ehlert, Stefan Grimme, Markus Bursch
Summary: Efficient quantum chemical methods are required for the computational treatment of large molecular structures. The ONIOM multi-layer scheme has been successfully implemented into the xtb program package and applied to transition-metal complexes with hundreds of atoms. By combining density functional theory, semi-empirical, and force-field methods in the ONIOM framework, computational costs can be significantly reduced without sacrificing accuracy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Tunga Salthammer, Uwe Hohm, Marcel Stahn, Stefan Grimme
Summary: Proton transfer reaction mass spectrometry (PTR-MS) is an important tool for indoor related sciences, allowing online monitoring and identification of substance mixtures in the gas phase. Kinetic laws and collision theory are used to quantify and calculate reaction rate constants under different conditions in the reaction chamber. The dipole moment and polarizability of organic compounds frequently found in indoor air were determined using advanced quantum mechanical methods, and their applicability in PTR-MS measurements was critically discussed.
Article
Chemistry, Multidisciplinary
Marcel Bamberg, Thomas Gasevic, Michael Bolte, Alexander Virovets, Hans-Wolfram Lerner, Stefan Grimme, Markus Bursch, Matthias Wagner
Summary: Treating perhydrogenated silafullerane [nBu(4)N][Cl@Si-20(SiH3)(12)H-8] with BBr3 resulted in partially and exhaustively brominated clusters, [nBu(4)N][Cl@Si-20(SiBr2H)(12)Br-8] and [nBu(4)N][Cl@Si-20(SiBr3)(12)Br-8], respectively. Full bromination increased steric strain on the cluster surface, enabling regioselective derivatization of the Si-32 framework under mild conditions. Partial Br/H exchange on [nBu(4)N][Cl@Si-20(SiBr2H)(12)Br-8] with iBu(2)AlH yielded [nBu(4)N][Cl@Si-20(SiH3)(12)Br-8].
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Vaibhav Bedi, Dipendu Mandal, Zahid Hussain, Shi-Ming Chen, Yile Wu, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The reaction of (tBuO(2)CN)(2) with 9-BBN leads to the formation of a bicyclic heterocyclic compound, while its reactions with BF3 or [Et3Si][B(C6F5)(4)] result in the isolation of different compounds. Computational studies reveal that the steric and electronic properties of the Lewis acid are important in the formation of one of the compounds.
DALTON TRANSACTIONS
(2024)
