Article
Multidisciplinary Sciences
Inbar Seroussi, Gadi Naveh, Zohar Ringel
Summary: Deep neural networks (DNNs) have complex structures, making direct microscopic analysis difficult. However, by identifying slow variables that average the behavior of fast variables, the authors have found a similar scale separation in finite deep convolutional neural networks and fully connected networks. They show that DNN layers couple through the second cumulant of their activations and pre-activations, which fluctuate in a Gaussian manner. The resulting thermodynamic theory of deep learning provides accurate predictions and new ways to understand DNNs.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Sason Shaik, David Danovich, Richard N. Zare
Summary: This paper describes the nature of hydrogen bond using valence bond theory. The analysis shows that polarization and charge transfer are the most important interactions in hydrogen bonds, and their sum is identical for different energy decomposition analysis methods. The total covalent-ionic resonance energy of the hydrogen bond is linearly correlated with the dissociation energy of the bond. The contributions of ionic structures to the hydrogen bond increase the positive charge on the hydrogen and contribute to catalytic reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
J. W. L. Lee, D. S. Tikhonov, P. Chopra, S. Maclot, A. L. Steber, S. Gruet, F. Allum, R. Boll, X. Cheng, S. Duesterer, B. Erk, D. Garg, L. He, D. Heathcote, M. Johny, M. M. Kazemi, H. Koeckert, J. Lahl, A. K. Lemmens, D. Loru, R. Mason, E. Mueller, T. Mullins, P. Olshin, C. Passow, J. Peschel, D. Ramm, D. Rompotis, N. Schirmel, S. Trippel, J. Wiese, F. Ziaee, S. Bari, M. Burt, J. Kuepper, A. M. Rijs, D. Rolles, S. Techert, P. Eng-Johnsson, M. Brouard, C. Vallance, B. Manschwetus, M. Schnell
Summary: Polycyclic aromatic hydrocarbons play a crucial role in interstellar chemistry, with high energy photons inducing ionization and fragmentation reactions. Through XUV-IR pump-probe experiments, the authors investigate the ultrafast photoinduced dynamics of fluorene, phenanthrene, and pyrene, shedding light on their preferred reaction pathways.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Linda Goletto, Tommaso Giovannini, Sarai D. Folkestad, Henrik Koch
Summary: The study investigated the coupling of different quantum-embedding approaches with a third molecular-mechanics layer, reducing computational cost and accurately reproducing specific solute-solvent interactions, such as hydrogen bonding.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Tim Gould, Leeor Kronik
Summary: This study reviews two important extensions of Kohn-Sham (KS) theory: generalized KS theory and ensemble KS theory. The former allows for non-multiplicative potential operators while the latter enables the treatment of quantum ensembles, offering improvements in efficiency for practical calculations. The research combines these two extensions and explores a computationally tractable variant for handling complex scenarios.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Inorganic & Nuclear
Zheng Zhang, Hadiah Fattal, Tielyr D. Creason, Mehran Amiri, Alexander Roseborough, Isaiah W. Gilley, May Nyman, Bayram Saparov
Summary: Recently, the solution chemistry of a model indium halide system, methylammonium (MA)-In-Br, was studied using a combination of various techniques. The results showed that under different loading ratios of reactants, indium could form either octahedral or tetrahedral anions in solution, or a combination of both. The understanding of the solution chemistry of this system led to the targeted crystallization of two novel compounds. These findings highlight the importance of understanding the solution chemistry of multinary metal halide systems for the discovery of functional materials for practical applications.
INORGANIC CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
Davis Zavickis, Kristians Kacars, Janis Cimurs, Andris Gulans
Summary: This paper presents an implementation of the adaptively compressed exchange (ACE) operator in the linearized-augmented plane waves formalism, and applies it to nonrelativistic total-energy calculations and the calculation of band gaps in solids. The results show that ACE operator, combined with the use of high-energy local orbitals, can achieve high precision in Fock exchange.
Article
Chemistry, Physical
Elan D. R. Mistry, Daphne Lubert-Perquel, Irena Nevjestic, Giuseppe Mallia, Pilar Ferrer, Kanak Roy, Georg Held, Tian Tian, Nicholas M. Harrison, Sandrine Heutz, Camille Petit
Summary: A family of boron nitride (BN)-based photocatalysts for solar fuel syntheses have recently emerged. Studies have shown that oxygen doping, leading to boron oxynitride (BNO), can extend light absorption to the visible range. This study demonstrates the importance of paramagnetic isolated OB3 states in inducing red-shifted light absorption and highlights the detrimental effects of diamagnetic O-B-O states on photochemistry in BNO semiconductors. The findings provide fundamental insights into the photophysics of BNO and pave the way for tailoring its optoelectronic and photochemical properties for solar fuel synthesis.
CHEMISTRY OF MATERIALS
(2023)
Article
Physics, Multidisciplinary
Pawel Zin, Maciej Pylak, Zbigniew Idziaszek, Mariusz Gajda
Summary: The article presents a formal description of the ground state of a weakly interacting Bose system, taking into account higher order terms in the energy expansion. This approach is applicable to a Bose-Bose mixture in a weak collapse regime where quantum fluctuations stabilize the system and lead to the formation of quantum liquid droplets. By using the generalized Gross-Pitaevskii equation and modified Bogoliubov equations, a self-consistent calculation of the renormalized anomalous density at zero temperature is derived, which is essential for accurately describing the formation of quantum liquid droplets.
NEW JOURNAL OF PHYSICS
(2022)
Review
Chemistry, Physical
Maria Belen Ruiz
Summary: This paper reviews the history of Half-Projected Hartree-Fock theory, provides a compilation of publications on this method, and discusses its extension to the calculation of excited states with the same symmetry.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2022)
Article
Chemistry, Physical
Laurent Lemmens, Xeno De Vriendt, Patrick Bultinck, Guillaume Acke
Summary: In this study, the spin phases and phase transitions during molecular dissociation in the presence of an external uniform magnetic field were explored. It was demonstrated that these spin phases can be interpreted and described by constraining the states to target expectation values of projected spin. The constrained states offer a complete electronic characterization and can be analyzed using standard quantum chemical tools.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Suhwan Song, Stefan Vuckovic, Eunji Sim, Kieron Burke
Summary: Fitting parameters in approximate density functionals often leads to errors from self-consistent densities and energy functionals being conflated. However, using density-corrected DFT can separate these errors. In some cases, using Hartree-Fock densities instead of self-consistent densities can provide more accurate results at no additional cost.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Sasha C. North, Nuno M. S. Almeida, Timothe R. L. Melin, Angela K. Wilson
Summary: In this study, CASSCF and MRCI+Q calculations were performed for LrF and LrO molecules, revealing 19 and 20 electronic states, respectively. Multiple dissociation channels were considered for both molecules, and various properties such as bond lengths, vibrational frequencies, anharmonicity constants, and excitation energies were calculated for the first time. Bond dissociation energies were also calculated using different levels of theory.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Review
Chemistry, Multidisciplinary
Franois Mouvet, Justin Villard, Viacheslav Bolnykh, Ursula Rothlisberger
Summary: This article introduces three methods to improve the efficiency of FPMD simulations, including an efficient implementation of FPMD-QM/MM simulations, specially devised multiple-time-step algorithms, and machine learning models. These methods significantly speed up FPMD simulations while preserving real-time dynamics and accuracy.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Physical
Hong-Zhou Ye, Timothy C. Berkelbach
Summary: In this study, distance-dependent estimators for two-center and three-center electron repulsion integrals over a short-range Coulomb potential were derived and demonstrated to be robust on periodic systems. These estimators provide tightness and are used with integral screening for calculating periodic three-center short-range Coulomb integrals with linear scaling.
JOURNAL OF CHEMICAL PHYSICS
(2021)