Article
Chemistry, Physical
Ali Eltareb, Gustavo E. Lopez, Nicolas Giovambattista
Summary: PIMD and RPMD simulations were used to study the properties of water and heavy water, revealing limitations in replicating the observed fluctuations in properties under supercooled conditions. Comparison with classical MD simulations showed minor differences in most properties, with exceptions in C-P(T), D(T), and structural properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Peihao Sun, Giulio Monaco, Peter Zalden, Klaus Sokolowski-Tinten, Jerzy Antonowicz, Ryszard Sobierajski, Yukio Kajihara, Alfred Q. R. Baron, Paul Fuoss, Andrew Chihpin Chuang, Jun-Sang Park, Jonathan Almer, J. B. Hastings
Summary: Liquid polymorphism is an interesting phenomenon observed in some single-component systems. By studying supercooled liquid Te, this research observes clear maxima in its thermodynamic response functions around a specific temperature, suggesting the possible existence of liquid polymorphism. The underlying structural evolution reveals the development of intermediate-range order, particularly around the temperature of the thermodynamic maxima, which is attributed to bond-orientational ordering. The similarities with water indicate that water-like anomalies may be a common phenomenon in liquid systems with competing bond-and density-ordering.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Anastasiia Garkul, Vladimir Stegailov
Summary: Compared to conventional first-order phase transitions, there has been less research on the kinetics of amorphous-amorphous transitions. This article presents a microscopic modeling approach using molecular dynamics to study the transformations between low-density and high-density amorphous ice. The study examines the dependence of elastic constants calculations on deformation rates and considers system size effects. The comparison with experimental data enhances our understanding of these transitions.
SCIENTIFIC REPORTS
(2022)
Article
Multidisciplinary Sciences
Cecilia Herrero, Michela Pauletti, Gabrile Tocci, Marcella Iannuzzi, Laurent Joly
Summary: Water is a unique fluid that has always been studied extensively by scientists. In this research, the temperature dependence of transport properties in water was investigated using density functional theory and ab initio molecular dynamics. The study found that different functionals have varying accuracy in describing experimental data and explored the role of nuclear quantum effects in water dynamics using machine learning algorithms. The molecular mechanisms underlying the performance of different functionals were also examined, and the relationship between structural properties and transport coefficients was verified. The results provide insights for predicting transport coefficients and developing improved functionals, emphasizing the importance of considering the long-range features of the radial distribution function.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Chemistry, Physical
Nicolas A. Loubet, Alejandro R. Verde, Jano A. Lockhart, Gustavo A. Appignanesi
Summary: Recent studies have confirmed the existence of a liquid-liquid critical point in numerical models of water. To properly characterize the different molecular arrangements, accurate structural indicators are needed. This study aims to investigate the effect of local structural constraints on water molecules in order to discriminate the different arrangements and develop a multi-molecule structural indicator.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Martin P. Andersson
Summary: Water, a crucial substance for life, exhibits numerous anomalous properties that can be explained by the formation of stable clusters under different temperature and pressure conditions. The configurational entropy of the hydrogen bond network within these clusters plays a significant role in the overall thermodynamic stability of water. Fluctuations in the water structure, rather than stable clusters, are observed due to the dynamic formation and reformation of these clusters.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Physical
Ingrid de Almeida Ribeiro, Maurice de Koning, Valeria Molinero
Summary: The anomalous increase in compressibility and heat capacity of supercooled water is attributed to a structural transformation into a four-coordinated liquid. Experimental studies show that kappa(T) and C-p reach their peaks at approximately 229 K. Recently, a pulsed heating procedure (PHP) revealed a significant increase in tetrahedrality around T-W(PHP) = 210 +/- 3 K. However, this discrepancy raises questions about whether the structure and thermodynamics of water are decoupled, or if the shift in T-W is an artifact of PHP.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Multidisciplinary Sciences
Loni Kringle, Wyatt A. Thornley, Bruce D. Kay, Greg A. Kimmel
Summary: The relaxation and crystallization processes of deeply supercooled water show different kinetic characteristics at different temperatures, corresponding to different initial structures. The structure of water can be reproduced by a linear combination of two local structural motifs, and a simple model can explain the complex kinetics within this context.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Materials Science, Multidisciplinary
Mohammed Bendjemai, Ahmed Azzouz Rached, Mudasser Husain, Ali Bentouaf, Nasir Rahman, Vineet Tirth, Ali Algahtani, Abdulaziz H. Alghtani, Tawfiq Al-Mughanam
Summary: In this study, the structural, thermodynamic, electronic, and mechanical properties of V2ScSnC2 and Nb2ScSnC2 MAX-phase quaternary compounds were investigated using the FP-LAPW approach. It was found that Nb2ScSnC2 is more stable and has better mechanical properties compared to V2ScSnC2. These compounds with high melting points and Debye temperatures are suitable for harsh environments and have potential applications as thermal barrier coatings. This study provides new insights for experimental researchers.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Chemistry, Physical
Ahmed Azzouz-Rached, M. A. Hadi, Habib Rached, Tariq Hadji, Djamel Rached, A. Bouhemadou
Summary: This study conducted a detailed theoretical investigation of the effects of pressure on the structural, elastic, magnetic, and thermodynamic properties of Mn2AlC and Mn2SiC MAX phases using density functional theory. The research found that Mn2AlC is a promising thermal barrier coating material, while Mn2SiC has a lower thermal expansion coefficient. The results of this study may inspire researchers worldwide to further explore the properties of MAX phases through experiments and theories.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Fausto Martelli, Jeremy C. Palmer
Summary: We investigated the spontaneous crystallization of water in the ST2 model under deeply supercooled conditions using molecular dynamics simulations. The ST2 model separates into low-density liquid and high-density liquid phases, promoting the formation of a sub-critical ice nucleus. Polymorphic selection favors the formation of cubic ice over hexagonal ice, and the critical nucleus absorbs both types of crystallites in the liquid phase.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Ming Ma, Junjie Song, Yi Dong, Weihai Fang, Lianghui Gao
Summary: In this study, a novel coarse-grained force field was developed to reproduce the structural and thermodynamic properties of triglycerides in bulk phase, as well as at air and water interfaces. The force field accurately reproduced the self-assembled network and diverse molecular conformations of triglycerides in water, and correctly predicted experimental macroscopic thermodynamic properties. This work paves the way for studying complex systems involving triglycerides on a larger scale.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Riccardo Foffi, John Russo, Francesco Sciortino
Summary: Recent research has shown that the TIP4P/Ice water model can be studied numerically at and below its liquid-liquid critical temperature. Through simulations along a subcritical isotherm, it was found that structural changes taking place across the liquid-liquid transition are influenced by the topological properties of the H-bond network. Specifically, the high-density liquid structure originates from the folding back of long rings, bringing pairs of molecules separated by several hydrogen-bonds close by in space.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Janus J. Eriksen
Summary: This study presents a robust protocol for probing localized electronic structure in condensed-phase systems, with initial application in liquid water where solvent-induced shift in dipole moment is significantly reduced. The methodology allows for evaluation of convergence of bulk properties, paving the way for future research on local effects and defects in more complex phases.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Kirill Gets, Ravil K. Zhdanov, Yulia Yu Bozhko, Vladimir R. Belosludov
Summary: Based on experimentally obtained clathrate hydrates structures, new ice phases were predicted using molecular and lattice dynamics methods. CS-IV was found to be a stable ice phase under negative pressure.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Multidisciplinary
Albert P. Bartok, Gyorgy Hantal, Livia B. Partay
Summary: We systematically explored the phase behavior of the hard-core two-scale ramp model suggested by Jagla, revealing a significantly richer phase diagram than previously anticipated. We identified new stable crystalline structures and showed that the new melting line is located at considerably higher temperature than the previously suggested boundary between low- and high-density liquid phases. The newly identified crystalline phases exhibit unexpectedly complex structural features, some of which are shared with the high-pressure ice VI phase.
PHYSICAL REVIEW LETTERS
(2021)
Editorial Material
Chemistry, Physical
Sergey N. N. Pozdnyakov, Michael J. J. Willatt, Albert P. P. Bartok, Christoph Ortner, Gabor Csanyi, Michele Ceriotti
Summary: This paper points out the degenerate pairs of configurations issue in all low-body-order atom-density correlation representations of molecular structures and discovers the quasi-constant smooth overlap of atomic position and atom-centered symmetry function fingerprint manifolds closely related to this problem. They demonstrate that the rigid singular configurations can only occur in finite, discrete sets and propose methods to optimize model parameters and the training set to mitigate their impact on machine learning models.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Trent Barnard, Steven Tseng, James P. Darby, Albert P. Bartok, Anders Broo, Gabriele C. Sosso
Summary: SOAP_GAS is a computational tool that uses genetic algorithms to optimize parameters for SOAP descriptors, leading to enhanced predictive capabilities.
MOLECULAR SYSTEMS DESIGN & ENGINEERING
(2023)
Article
Chemistry, Physical
Jan Kloppenburg, Livia B. Partay, Hannes Jonsson, Miguel A. Caro
Summary: A Gaussian approximation machine learning interatomic potential for platinum is developed based on density-functional theory (DFT) data. The potential exhibits excellent transferability and agreement with DFT in various properties such as bulk elasticity, surface energetics, and nanoparticle stability. It provides state-of-the-art accuracy at a low computational cost. Two examples are presented to demonstrate the potential's capability in modeling Pt systems: the pressure-temperature phase diagram of Pt calculated using nested sampling and a study of the spontaneous crystallization of a large Pt nanoparticle based on classical dynamics simulations over several nanoseconds.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Computer Science, Artificial Intelligence
Sascha Klawohn, James R. Kermode, Albert P. Bartok
Summary: We introduce a data-parallel software package that fits Gaussian approximation potentials (GAPs) on multiple nodes using ScaLAPACK library with MPI and OpenMP. This implementation overcomes the memory limitation of training set size for GAP models on a single compute node and achieves parallel descriptor evaluation and linear solve. The scalability of our approach allows for efficient fitting of GAP models on thousands of cores and opens up opportunities for complex systems and higher-level workflows.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Physical
Sascha Klawohn, James P. Darby, James R. Kermode, Gabor Csanyi, Miguel A. Caro, Albert P. Bartok
Summary: This article introduces the theory, algorithms, and software implementation of Gaussian Approximation Potentials (GAPs), and provides usage examples. Additionally, recent developments in the GAP framework are discussed.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
Giovanni Garberoglio, Christof Gaiser, Roberto M. Gavioso, Allan H. Harvey, Robert Hellmann, Bogumil Jeziorski, Karsten Meier, Michael R. Moldover, Laurent Pitre, Krzysztof Szalewicz, Robin Underwood
Summary: This article reviews recent advances in the interplay between ab initio calculations and metrology, focusing on gas-based techniques for temperature and pressure measurements. Since around 2010, several thermophysical quantities can be computed from first principles with high accuracy, surpassing experimental data and contributing to primary metrology. The availability of ab initio virial and transport coefficients has facilitated measurements of the Boltzmann constant and the development of primary standards for thermodynamic temperature and pressure.
JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA
(2023)
Article
Chemistry, Physical
Jakub Lang, Giovanni Garberoglio, Michal Przybytek, Malgorzata Jeziorska, Bogumil Jeziorski
Summary: The non-additive three-body interaction potential for helium was computed using the coupled-cluster theory and the full configuration interaction method. An improved nonrelativistic Born-Oppenheimer energy and the leading relativistic and nuclear-motion corrections were included in the obtained potential. The calculated uncertainties were found to be 1.2%, and the three-body potential for helium was determined to be 90.6 mK with an estimated uncertainty of 0.5 mK when three helium atoms form an equilateral triangle.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Computer Science, Artificial Intelligence
Connor Allen, Albert P. Bartok
Summary: This article presents a computationally efficient method for generating databases of atomic configurations that contain optimal information on the small-displacement regime of the potential energy surface of bulk crystalline matter, with successful application in reproducing the phonon and elastic properties.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Greg Ashton, Noam Bernstein, Johannes Buchner, Xi Chen, Gabor Csanyi, Andrew Fowlie, Farhan Feroz, Matthew Griffiths, Will Handley, Michael Habeck, Edward Higson, Michael Hobson, Anthony Lasenby, David Parkinson, Livia B. Partay, Matthew Pitkin, Doris Schneider, Joshua S. Speagle, Leah South, John Veitch, Philipp Wacker, David J. Wales, David Yallup
Summary: This Primer examines Skilling's nested sampling algorithm and its application in Bayesian inference and multidimensional integration. The principles of nested sampling are summarized and recent developments using efficient nested sampling algorithms in high dimensions are surveyed. Detailed examples from cosmology, gravitational-wave astronomy, and materials science are provided. Finally, the Primer includes recommendations for best practices and a discussion of potential limitations and optimizations of nested sampling.
NATURE REVIEWS METHODS PRIMERS
(2022)
Correction
Multidisciplinary Sciences
Greg Ashton, Noam Bernstein, Johannes Buchner, Xi Chen, Gabor Csanyi, Andrew Fowlie, Farhan Feroz, Matthew Griffiths, Will Handley, Michael Habeck, Edward Higson, Michael Hobson, Anthony Lasenby, David Parkinson, Livia B. Partay, Matthew Pitkin, Doris Schneider, Joshua S. Speagle, Leah South, John Veitch, Philipp Wacker, David J. Wales, David Yallup
NATURE REVIEWS METHODS PRIMERS
(2022)
Article
Chemistry, Physical
Livia B. Partay, Gyoergy Hantal
Summary: This study computed the pressure-temperature phase diagram of the hard-core two-scale ramp potential in two dimensions, revealing the sensitivity of phases stability through parameterization and model modifications. It identified thermodynamically relevant phases and proposed a smooth version of the potential that reproduces density anomaly and forms a dodecahedral quasi-crystal structure.
Article
Optics
Matteo Sighinolfi, Davide De Boni, Alessandro Roggero, Giovanni Garberoglio, Pietro Faccioli, Alessio Recati
Summary: This study investigates the dynamics of heavy impurities in ultracold Fermi gases using a generalized Langevin equation. By predicting the existence of bound states in the two-impurity case, we provide testable methods for our predictions.
Article
Chemistry, Multidisciplinary
Andrea Pedrielli, Paolo E. Trevisanutto, Lorenzo Monacelli, Giovanni Garberoglio, Nicola M. Pugno, Simone Taioli
Summary: Magnesium hydride nanoparticles (NPs) have been studied for hydrogen storage, showing reduced desorption temperature. The interatomic bond lengths exhibit a linear dependence on temperature, with a decrease in Mg-H bond length. A machine learning model is used to accurately determine forces and total energies, integrating the model with anharmonic effects. Hydrogen desorption temperature decreases significantly, with little effect from anharmonicities.
Article
Materials Science, Multidisciplinary
Heikki Muhli, Xi Chen, Albert P. Bartok, Patricia Hernandez-Leon, Gabor Csanyi, Tapio Ala-Nissila, Miguel A. Caro
Summary: The researchers proposed a comprehensive methodology to add van der Waals corrections to machine learning atomistic force fields, which accurately learns atomic polarizabilities to describe vdW interactions and enables efficient computation as well as straightforward calculation of observable gradients. The effectiveness of this method was demonstrated through the study of the phase diagram of C-60 molecules.