Article
Chemistry, Physical
David Loffreda, Dawn M. Foster, Richard E. Palmer, Nathalie Tarrat
Summary: Scanning transmission electron microscopy experiments confirm that the predominant ordered structure for Ag309 nanoclusters is face-centered cubic (FCC). Density functional theory calculations reveal the influence of defects and symmetry changes on stability, with FCC and decahedral symmetries being more favorable than icosahedral. The proposal of a surface atomic density descriptor provides a qualitative reproduction of surface energy data, indicating that nonsymmetric and defective structures may be preferred within a certain size range.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Francesco Isaia, Alessandra Garau, Carlo Castellano, Francesco Demartin, M. Carla Aragoni, Massimiliano Arca, Claudia Caltagirone, Vito Lippolis, Tiziana Pivetta
Summary: The reaction between CsOH and parabanic acid results in the formation of the caesium salt of the oxalurate anion, while the reaction with cyanuric acid leads to a CsOH co-crystal of cyanuric acid. The X-ray crystal structures of these compounds show robust homomeric ribbons formed by organic moieties, with Cs+ ions stabilized regardless of the charge of the ribbon.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Sang Loon Tan, Yee Seng Tan, Muhammad Syafiq Bin Shahari, Ahmad Junaid, Anton Dolzhenko, Edward R. T. Tiekink
Summary: Two polymorphs, alpha and beta, of an N-2,6-diaryl-1,3,5-triazine-2,4-diamine derivative have been isolated and show distinct molecular packing and stability of molecular conformation. The alpha-polymorph features expansive, stabilising pi stacking interactions achieved by relatively unstable conformations. The beta-polymorph is the thermodynamically stable form and can be obtained by the conversion of the alpha-polymorph over time or by heating.
Article
Chemistry, Physical
Yong Lu, Mingjun Chen, Yi Wang, Yunhai Hu, Xiaoxu Wang, Wenming Zhang, Zhanyu Li
Summary: Aluminum ion batteries (AIBs) are considered the most promising large-scale metal ion batteries due to their high safety and eco-friendly characteristics. To overcome the weak electrical conductivity issue of organic materials, various cyano organic molecules with electrophilic properties are chosen as the cathode materials for aluminum batteries. Through experimental characterization and theoretical calculations, Phthalonitrile is identified as the best cathode material among the five organic molecules and C≡N group is found to be the active site for the insertion/extraction of AlCl2+ ions. The assembled flexible package battery exhibits a high initial specific capacity of 191.92 mAh g(-1), a discharge-specific capacity of 112.67 mAh g(-1) after 1000 cycles, and a coulombic efficiency of ≈97%. Furthermore, the influence of different molecular structures and functional groups on the battery performance is also demonstrated. These research findings lay the foundation for selecting safe and stable organic aluminum batteries and provide a new reference for the development of high-performance AIBs.
Article
Polymer Science
Steve R. Lustig, Jan W. Andzelm, Eric D. Wetzel
Summary: A comparative study of linear and two-dimensional polyaramids at high temperatures reveals that 2D polymers offer higher thermal resilience and structural stability, making them advantageous for high temperature applications.
Article
Chemistry, Physical
James Chapman, Nir Goldman, Brandon C. Wood
Summary: In this study, a graph-based order parameter is introduced for the characterization of atomistic structures. The order parameter is universal and transferable to different structural geometries, outperforming existing methods in classifying atomistic structures and opening up possibilities for fine structure-level characterization.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Satter Rohman, Rahul Kar
Summary: Thermally activated delayed fluorescence (TADF) has applications in organic light-emitting diodes. In this study, two efficient descriptor-based tuning schemes (ELF and Sol) were used to accurately compute the excited-state properties of TADF emitters. The results showed that these tuned functionals performed consistently in different solvent dielectrics and exhibited good accuracy in calculating small experimental singlet-triplet gaps.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Isuru R. Ariyarathna
Summary: A systematic electronic structure analysis was conducted on M(L)(n) molecular electrides and their corresponding alkalide units M(L)(n) @M' (M/M' = Na, K; L = Tren, Azacryptand, TriPip222; n = 1, 2). The complexes were found to belong to the superalkali category with low ionization potentials. The saturated molecular electrides displayed a diffuse quasispherical electron cloud, making them superatoms. The alkalide complexes had ionic structures and their dissociation energies varied in a specific sequence. The anions of the alkalide units occupied diffuse Rydberg-like orbitals. Excited states and trends were also analyzed.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Sayan Banerjee, Andrew M. Rappe
Summary: In this study, we investigate the use of graphene curvature for directional molecular motion and provide atomistic insights into curvature-dependent molecular migration. We demonstrate that the migration of molecules on wrinkled/rippled graphene sheets preferentially occurs from positive to negative curvature regions. Based on these findings, we suggest exploring other two-dimensional materials for controlled molecular motion.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Thomas C. Pitts, Nektarios N. Lathiotakis, Nikitas Gidopoulos
Summary: The proposed new method utilizes a generalized Kohn-Sham or constrained hybrid approach to accurately determine the single-particle eigenvalue spectrum, achieving improvements in the total energy.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Fatemeh Tavakoli-Quchani, Alireza Salimi, Behrouz Notash, Ali Samie, Jered C. Garrison
Summary: In this study, a carboxamide compound was designed and synthesized. Three high Z' polymorphic structures were found to exist. The structural features of the polymorphs were investigated experimentally and theoretically, and hydrogen bond interactions were found to play a key role in the aggregation of the molecular structures. Interestingly, the axis previously reported to contribute to the high Z' was present in all obtained polymorphs.
Article
Chemistry, Multidisciplinary
Chinmoy Das, Taichi Nishiguchi, Zeyu Fan, Satoshi Horike
Summary: This study investigated the mechanism of crystal melting and crystallization behavior of a two-dimensional coordination polymer during heating-cooling processes. The results showed that the coordination bond networks were partially retained in the melt state and the melt had a significantly lower viscosity compared to other samples. Rheological studies provided insights into the fast relaxation dynamics of the recrystallization process.
Article
Multidisciplinary Sciences
Zuodong Sun, Cooper S. Jamieson, Masao Ohashi, K. N. Houk, Yi Tang
Summary: This study reports the discovery of a norbornene synthase SdnG and its role in the biosynthesis of the antifungal natural product sordarin. The reconstitution of sordarin biosynthesis reveals a concise oxidative strategy used by Nature to transform a hydrocarbon precursor into a highly functionalized substrate for SdnG. It was found that SdnG generates the norbornene core of sordarin and accelerates the intramolecular Diels-Alder reaction.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Sayan Banerjee, Nathaniel Hawthorne, James D. Batteas, Andrew M. Rappe
Summary: This study investigates controllable molecular motion at the nanoscale by studying the migration of a molecule on curved graphene. The researchers find that directional ring migration can be achieved on graphene with different curvatures. By controlling the extent of covalent bonding between graphene and the molecule, the researchers can control the binding energy gradient and drive molecular migration. This study provides a new way to tune the electronic structure of two-dimensional materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jenny W. Fothergill, Adam C. Colson, Matthew D. King
Summary: This study utilized density functional theory to computationally investigate the crystal properties of pDPUs, exploring the impact of substituents on intermolecular interactions and crystallization behaviors of organometallic derivatives. The results contribute to the design rules for patterned crystal growth of DPU and related systems, facilitating the development of innovative materials with unique solid-state properties.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Chemistry, Medicinal
Lincan Fang, Xiaomi Guo, Milica Todorovic, Patrick Rinke, Xi Chen
Summary: Finding low-energy conformers of organic molecules on nanoclusters is a complex problem, which is further complicated by the constraints imposed by the presence of the cluster and other surrounding molecules. In this study, we modified our active learning molecular conformer search method to address this challenge, particularly focusing on avoiding steric clashes between the molecule and the cluster. Using a cysteine molecule on a gold-thiolate cluster as a model system, we demonstrated that the conformers in the cluster inherited the hydrogen bond types from isolated conformers but exhibited reordered energy rankings and spacings.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2023)
Article
Chemistry, Physical
Johannes T. Margraf, Hyunwook Jung, Christoph Scheurer, Karsten Reuter
Summary: Chemical reaction networks are crucial for understanding heterogeneous catalytic processes. However, inferring networks from experiments alone is challenging due to the lack of microscopic information. Computational approaches provide insights but come with uncertainties. This Perspective highlights the applications of machine learning in catalytic reaction networks, aiding in both experimental inference and computational exploration.
Article
Chemistry, Physical
Simiam Ghan, Elias Diesen, Christian Kunkel, Karsten Reuter, Harald Oberhofer
Summary: We investigate the electronic coupling between an adsorbate and a metal surface by directly calculating tunneling matrix elements H-ad based on first principles. Using a projection-operator diabatization approach, we project the Kohn-Sham Hamiltonian onto a diabatic basis. By integrating the couplings over the Brillouin zone, we are able to calculate a size-convergent Newns-Anderson chemisorption function, which measures the broadening of an adsorbate frontier state upon adsorption. This function reveals not only the lifetime of the electron state, but also provides rich information on orbital phase interactions on the surface.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Jarno Laakso, Lauri Himanen, Henrietta Homm, Eiaki V. Morooka, Marc O. J. Jager, Milica Todorovic, Patrick Rinke
Summary: We present an update to the DScribe package that adds the Valle-Oganov materials fingerprint as a descriptor selection and provides descriptor derivatives for advanced machine learning tasks. Numeric derivatives are now available for all descriptors in DScribe, and analytic derivatives are implemented for MBTR and SOAP. We demonstrate the effectiveness of descriptor derivatives in machine learning models for Cu clusters and perovskite alloys.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
R. Dupuy, J. Filser, C. Richter, T. Buttersack, F. Trinter, S. Gholami, R. Seidel, C. Nicolas, J. Bozek, D. Egger, H. Oberhofer, S. Thuermer, U. Hergenhahn, K. Reuter, B. Winter, H. Bluhm
Summary: The determination of depth profiles across interfaces is crucial in various scientific and technological fields. While photoemission spectroscopy is a suitable method for this purpose, investigating liquid-vapor interfaces has been hindered by a lack of understanding of electron-scattering processes in liquids. However, recent studies have shown that core-level photoelectron angular distributions can provide information on the depth distribution of species across the interface. This study further explores this concept and demonstrates that the experimental anisotropy parameter scales linearly with the average distance of atoms along the surface normal, achieving excellent depth resolution.
PHYSICAL REVIEW LETTERS
(2023)
Article
Psychology, Experimental
Yuqing Zhao, Ting Zeng, Tongyu Wang, Fang Fang, Yi Pan, Jianrong Jia
Summary: This study found that statistical encoding compresses redundant information from multiple items into a single summary metric. The researchers examined the involvement of the subcortex in processing summary statistics and found that invisible circles were automatically included in the statistical representation, but only when presented to the same eye as visible circles.
Article
Chemistry, Physical
Pascal Henkel, Jingrui Li, G. Krishnamurthy Grandhi, Paola Vivo, Patrick Rinke
Summary: Quaternary mixed-metal chalcohalides (Sn2M(III)Ch(2)X(3)) are emerging as promising lead-free, perovskite-inspired photovoltaic absorbers. Density functional theory was used to identify lead-free Sn2M(III)Ch(2)X(3) materials that are structurally and energetically stable within specific space groups and have a suitable band gap for outdoor and indoor photovoltaic applications. Promising materials were identified and potential alloys for band gap tuning were proposed.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Martin Vondrak, Karsten Reuter, Johannes T. T. Margraf
Summary: This paper presents the q-pac Python package, which implements several algorithmic and methodological advances to the kQEq method and provides an extendable framework for the development of ML charge equilibration models.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
King Chun Lai, Sebastian Matera, Christoph Scheurer, Karsten Reuter
Summary: The nature of an atom in a bonded structure depends on its local atomic environment. Identifying groups of atoms with equivalent environments is a frequent task in atomic-scale modeling and simulation, and we present a machine-learning framework to automate this task.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sina Stocker, Hyunwook Jung, Gabor Csanyi, C. Franklin Goldsmith, Karsten Reuter, Johannes T. Margraf
Summary: This study demonstrates that machine-learning methods can be used to predict the rate constants of elementary reaction steps in catalytic processes. The results show that thermal effects have a significant impact on the free energy barriers, which can be different from the predictions based on the harmonic transition state theory approximation. This finding calls into question the previously reported mechanisms established by microkinetic models.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Multidisciplinary
Ke Chen, Christian Kunkel, Bingqing Cheng, Karsten Reuter, Johannes T. Margraf
Summary: Machine learning is widely used in predicting chemical properties, especially energies and forces in molecules and materials. However, some electronic properties do not scale linearly with system size, leading to large errors when using size-extensive models. This study explores different strategies to learn intensive and localized properties, focusing on HOMO energies in organic molecules.
Article
Mathematical & Computational Biology
Tongyu Wang, Yadong Chen
Summary: This paper studies the vibration suppression control of a flexible manipulator system modeled by partial differential equation (PDE) with state constraints. The problem of joint angle constraint and boundary vibration deflection is solved using the Barrier Lyapunov function (BLF) based on the backstepping recursive design framework. Furthermore, an event-triggered mechanism is proposed based on the relative threshold strategy to save communication workload and improve system efficiency. Simulation results prove the effectiveness of the proposed control strategy in achieving good damping effect on vibration and elevated system performance.
MATHEMATICAL BIOSCIENCES AND ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Hilda Sandstrom, Matti Rissanen, Juho Rousu, Patrick Rinke
Summary: This article provides an overview of the current state of data-driven compound identification with mass spectrometry in atmospheric science. It discusses the challenges and future steps towards a digital era in atmospheric mass spectrometry. Enhancing atmospheric compound identification is crucial for understanding atmospheric processes, and mass spectrometry enables fast and accurate identification in both field and laboratory settings. Digitizing identification protocols may expedite new compound discovery, but it requires relevant reference standards and the establishment of a collaborative, open data infrastructure.
Article
Chemistry, Physical
Nicolas Bergmann, Nicolas G. Hoermann, Karsten Reuter
Summary: This study investigates the approximations used in computationally efficient calculations for the electrosorption of Br ions on an Ag(100) model electrode. The combination of an implicit solvation model, a perturbative second order account of capacitive double layer effects, and a constant-potential grand-canonical Monte Carlo sampling of the adsorbate layer accurately describes the experimental results. However, error cancellation at lower levels of theory may also lead to good descriptions, despite inadequate treatment of key underlying physics, such as the disorder-order transition of the Br adlayer.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Multidisciplinary
Tobias Weiss, Aleksandr Baklanov, Georg S. Michelitsch, Karsten Reuter, Martin Schwarz, Manuela Garnica, Willi Auwarter
Summary: This study presents the first real space characterization of borazine molecules and their self-assemblies on solid supports. The adsorption of borazine on Ag(111) surface is weak and non-dissociative, with the ring aligned parallel to the surface plane. Borazine molecules prefer hollow adsorption sites, leading to the assembly of both porous and dense-packed structures. STM-based manipulation is demonstrated to modify the borazine adsorption configuration.
ADVANCED MATERIALS INTERFACES
(2023)