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Gallegos M, Vassilev-Galindo V, Poltavsky I, Martín Pendás Á, Tkatchenko A. Explainable chemical artificial intelligence from accurate machine learning of real-space chemical descriptors. Nat Commun 2024; 15:4345. [PMID: 38773090 DOI: 10.1038/s41467-024-48567-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 04/24/2024] [Indexed: 05/23/2024] Open
Abstract
Machine-learned computational chemistry has led to a paradoxical situation in which molecular properties can be accurately predicted, but they are difficult to interpret. Explainable AI (XAI) tools can be used to analyze complex models, but they are highly dependent on the AI technique and the origin of the reference data. Alternatively, interpretable real-space tools can be employed directly, but they are often expensive to compute. To address this dilemma between explainability and accuracy, we developed SchNet4AIM, a SchNet-based architecture capable of dealing with local one-body (atomic) and two-body (interatomic) descriptors. The performance of SchNet4AIM is tested by predicting a wide collection of real-space quantities ranging from atomic charges and delocalization indices to pairwise interaction energies. The accuracy and speed of SchNet4AIM breaks the bottleneck that has prevented the use of real-space chemical descriptors in complex systems. We show that the group delocalization indices, arising from our physically rigorous atomistic predictions, provide reliable indicators of supramolecular binding events, thus contributing to the development of Explainable Chemical Artificial Intelligence (XCAI) models.
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Affiliation(s)
- Miguel Gallegos
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006, Oviedo, Spain
| | | | - Igor Poltavsky
- Department of Physics and Materials Science, University of Luxembourg, L-1511, Luxembourg City, Luxembourg
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006, Oviedo, Spain.
| | - Alexandre Tkatchenko
- Department of Physics and Materials Science, University of Luxembourg, L-1511, Luxembourg City, Luxembourg.
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2
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Gallegos M, Guevara-Vela JM, Pendás ÁM. NNAIMQ: A neural network model for predicting QTAIM charges. J Chem Phys 2022; 156:014112. [PMID: 34998318 DOI: 10.1063/5.0076896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Atomic charges provide crucial information about the electronic structure of a molecular system. Among the different definitions of these descriptors, the one proposed by the Quantum Theory of Atoms in Molecules (QTAIM) is particularly attractive given its invariance against orbital transformations although the computational cost associated with their calculation limits its applicability. Given that Machine Learning (ML) techniques have been shown to accelerate orders of magnitude the computation of a number of quantum mechanical observables, in this work, we take advantage of ML knowledge to develop an intuitive and fast neural network model (NNAIMQ) for the computation of QTAIM charges for C, H, O, and N atoms with high accuracy. Our model has been trained and tested using data from quantum chemical calculations in more than 45 000 molecular environments of the near-equilibrium CHON chemical space. The reliability and performance of NNAIMQ have been analyzed in a variety of scenarios, from equilibrium geometries to molecular dynamics simulations. Altogether, NNAIMQ yields remarkably small prediction errors, well below the 0.03 electron limit in the general case, while accelerating the calculation of QTAIM charges by several orders of magnitude.
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Affiliation(s)
- Miguel Gallegos
- Depto. Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, Spain
| | - José Manuel Guevara-Vela
- Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán, Mexico City C.P. 04510, Mexico
| | - Ángel Martín Pendás
- Depto. Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, Spain
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3
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Landeros-Rivera B, Gallegos M, Munarriz J, Laplaza R, Contreras García J. New venues in electron density analysis. Phys Chem Chem Phys 2022; 24:21538-21548. [DOI: 10.1039/d2cp01517j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide a comprehensive overview of the chemical information within the electron density: how to extract information, but also how to obtain and how to assess the quality of the...
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4
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Broad J, Preston S, Wheatley RJ, Graham RS. Gaussian process models of potential energy surfaces with boundary optimization. J Chem Phys 2021; 155:144106. [PMID: 34654292 DOI: 10.1063/5.0063534] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A strategy is outlined to reduce the number of training points required to model intermolecular potentials using Gaussian processes, without reducing accuracy. An asymptotic function is used at a long range, and the crossover distance between this model and the Gaussian process is learnt from the training data. The results are presented for different implementations of this procedure, known as boundary optimization, across the following dimer systems: CO-Ne, HF-Ne, HF-Na+, CO2-Ne, and (CO2)2. The technique reduces the number of training points, at fixed accuracy, by up to ∼49%, compared to our previous work based on a sequential learning technique. The approach is readily transferable to other statistical methods of prediction or modeling problems.
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Affiliation(s)
- Jack Broad
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Simon Preston
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Richard J Wheatley
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Richard S Graham
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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5
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Di Pasquale N, Elliott JD, Hadjidoukas P, Carbone P. Dynamically Polarizable Force Fields for Surface Simulations via Multi-output Classification Neural Networks. J Chem Theory Comput 2021; 17:4477-4485. [PMID: 34197102 DOI: 10.1021/acs.jctc.1c00360] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a general procedure to introduce electronic polarization into classical Molecular Dynamics (MD) force fields using a Neural Network (NN) model. We apply this framework to the simulation of a solid-liquid interface where the polarization of the surface is essential to correctly capture the main features of the system. By introducing a multi-input, multi-output NN and treating the surface polarization as a discrete classification problem, we are able to obtain very good accuracy in terms of quality of predictions. Through the definition of a custom loss function we are able to impose a physically motivated constraint within the NN itself making this model extremely versatile, especially in the modeling of different surface charge states. The NN is validated considering the redistribution of electronic charge density within a graphene based electrode in contact with an aqueous electrolyte solution, a system highly relevant to the development of next generation low-cost supercapacitors. We compare the performances of our NN/MD model against Quantum Mechanics/Molecular Dynamics simulations where we obtain a most satisfactory agreement.
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Affiliation(s)
- Nicodemo Di Pasquale
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9AL, United Kingdom
| | - Joshua D Elliott
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9AL, United Kingdom
| | | | - Paola Carbone
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9AL, United Kingdom
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6
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Konovalov A, Symons BCB, Popelier PLA. On the many-body nature of intramolecular forces in FFLUX and its implications. J Comput Chem 2020; 42:107-116. [PMID: 33107993 DOI: 10.1002/jcc.26438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/28/2020] [Accepted: 09/28/2020] [Indexed: 12/24/2022]
Abstract
FFLUX is a biomolecular force field under construction, based on Quantum Chemical Topology (QCT) and machine learning (kriging), with a minimalistic and physically motivated design. A detailed analysis of the forces within the kriging models as treated in FFLUX is presented, taking as a test example a liquid water model. The energies of topological atoms are modeled as 3Natoms -6 dimensional potential energy surfaces, using atomic local frames to represent the internal degrees of freedom. As a result, the forces within the kriging models in FFLUX are inherently N-body in nature where N refers to Natoms . This provides a fuller picture that is closer to a true quantum mechanical representation of interactions between atoms. The presented computational example quantitatively showcases the non-negligible (as much as 9%) three-body nature of bonded forces and angular forces in a water molecule. We discuss the practical impact on the pressure calculation with N-body forces and periodic boundary conditions (PBC) in molecular dynamics, as opposed to classical force fields with two-body forces. The equivalence between the PBC-related correction terms in the general virial equation is shown mathematically.
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Affiliation(s)
- Anton Konovalov
- Manchester Institute of Biotechnology (MIB), Manchester, United Kingdom.,Department of Chemistry, University of Manchester, Manchester, United Kingdom
| | - Benjamin C B Symons
- Manchester Institute of Biotechnology (MIB), Manchester, United Kingdom.,Department of Chemistry, University of Manchester, Manchester, United Kingdom
| | - Paul L A Popelier
- Manchester Institute of Biotechnology (MIB), Manchester, United Kingdom.,Department of Chemistry, University of Manchester, Manchester, United Kingdom
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7
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Guevara-Vela JM, Francisco E, Rocha-Rinza T, Martín Pendás Á. Interacting Quantum Atoms-A Review. Molecules 2020; 25:E4028. [PMID: 32899346 PMCID: PMC7504790 DOI: 10.3390/molecules25174028] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 12/16/2022] Open
Abstract
The aim of this review is threefold. On the one hand, we intend it to serve as a gentle introduction to the Interacting Quantum Atoms (IQA) methodology for those unfamiliar with it. Second, we expect it to act as an up-to-date reference of recent developments related to IQA. Finally, we want it to highlight a non-exhaustive, yet representative set of showcase examples about how to use IQA to shed light in different chemical problems. To accomplish this, we start by providing a brief context to justify the development of IQA as a real space alternative to other existent energy partition schemes of the non-relativistic energy of molecules. We then introduce a self-contained algebraic derivation of the methodological IQA ecosystem as well as an overview of how these formulations vary with the level of theory employed to obtain the molecular wavefunction upon which the IQA procedure relies. Finally, we review the several applications of IQA as examined by different research groups worldwide to investigate a wide variety of chemical problems.
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Affiliation(s)
- José Manuel Guevara-Vela
- Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán C.P., Mexico City 04510, Mexico; (J.M.G.-V.); (T.R.-R.)
| | - Evelio Francisco
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006 Oviedo, Spain;
| | - Tomás Rocha-Rinza
- Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán C.P., Mexico City 04510, Mexico; (J.M.G.-V.); (T.R.-R.)
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo, E-33006 Oviedo, Spain;
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8
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Burn MJ, Popelier PLA. Creating Gaussian process regression models for molecular simulations using adaptive sampling. J Chem Phys 2020; 153:054111. [DOI: 10.1063/5.0017887] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Matthew J. Burn
- Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom and Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Paul L. A. Popelier
- Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, United Kingdom and Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
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9
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Silva AF, Duarte LJ, Popelier PLA. Contributions of IQA electron correlation in understanding the chemical bond and non-covalent interactions. Struct Chem 2020. [DOI: 10.1007/s11224-020-01495-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AbstractThe quantum topological energy partitioning method Interacting Quantum Atoms (IQA) has been applied for over a decade resulting in an enlightening analysis of a variety of systems. In the last three years we have enriched this analysis by incorporating into IQA the two-particle density matrix obtained from Møller–Plesset (MP) perturbation theory. This work led to a new computational and interpretational tool to generate atomistic electron correlation and thus topologically based dispersion energies. Such an analysis determines the effects of electron correlation within atoms and between atoms, which covers both bonded and non-bonded “through -space” atom–atom interactions within a molecule or molecular complex. A series of papers published by us and other groups shows that the behavior of electron correlation is deeply ingrained in structural chemistry. Some concepts that were shown to be connected to bond correlation are bond order, multiplicity, aromaticity, and hydrogen bonding. Moreover, the concepts of covalency and ionicity were shown not to be mutually excluding but to both contribute to the stability of polar bonds. The correlation energy is considerably easier to predict by machine learning (kriging) than other IQA terms. Regarding the nature of the hydrogen bond, correlation energy presents itself in an almost contradicting way: there is much localized correlation energy in a hydrogen bond system, but its overall effect is null due to internal cancelation. Furthermore, the QTAIM delocalization index has a connection with correlation energy. We also explore the role of electron correlation in protobranching, which provides an explanation for the extra stabilization present in branched alkanes compared to their linear counterparts. We hope to show the importance of understanding the true nature of the correlation energy as the foundation of a modern representation of dispersion forces for ab initio, DFT, and force field calculations.
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10
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Chen T, Manz TA. A collection of forcefield precursors for metal-organic frameworks. RSC Adv 2019; 9:36492-36507. [PMID: 35539031 PMCID: PMC9075174 DOI: 10.1039/c9ra07327b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022] Open
Abstract
A host of important performance properties for metal-organic frameworks (MOFs) and other complex materials can be calculated by modeling statistical ensembles. The principle challenge is to develop accurate and computationally efficient interaction models for these simulations. Two major approaches are (i) ab initio molecular dynamics in which the interaction model is provided by an exchange-correlation theory (e.g., DFT + dispersion functional) and (ii) molecular mechanics in which the interaction model is a parameterized classical force field. The first approach requires further development to improve computational speed. The second approach requires further development to automate accurate forcefield parameterization. Because of the extreme chemical diversity across thousands of MOF structures, this problem is still mostly unsolved today. For example, here we show structures in the 2014 CoRE MOF database contain more than 8 thousand different atom types based on first and second neighbors. Our results showed that atom types based on both first and second neighbors adequately capture the chemical environment, but atom types based on only first neighbors do not. For 3056 MOFs, we used density functional theory (DFT) followed by DDEC6 atomic population analysis to extract a host of important forcefield precursors: partial atomic charges; atom-in-material (AIM) C6, C8, and C10 dispersion coefficients; AIM dipole and quadrupole moments; various AIM polarizabilities; quantum Drude oscillator parameters; AIM electron cloud parameters; etc. Electrostatic parameters were validated through comparisons to the DFT-computed electrostatic potential. These forcefield precursors should find widespread applications to developing MOF force fields.
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Affiliation(s)
- Taoyi Chen
- Department of Chemical & Materials Engineering, New Mexico State University Las Cruces New Mexico 88003-8001 USA
| | - Thomas A Manz
- Department of Chemical & Materials Engineering, New Mexico State University Las Cruces New Mexico 88003-8001 USA
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11
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Interplay of thermochemistry and Structural Chemistry, the journal (volume 28, 2017, issues 5–6), and the discipline. Struct Chem 2018. [DOI: 10.1007/s11224-018-1217-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Di Pasquale N, Davie SJ, Popelier PLA. The accuracy of ab initio calculations without ab initio calculations for charged systems: Kriging predictions of atomistic properties for ions in aqueous solutions. J Chem Phys 2018; 148:241724. [DOI: 10.1063/1.5022174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Nicodemo Di Pasquale
- Manchester Institute of Biotechnology (MIB), 131 Princess
Street, Manchester M1 7DN, United Kingdom and School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL,
United Kingdom
| | - Stuart J. Davie
- Manchester Institute of Biotechnology (MIB), 131 Princess
Street, Manchester M1 7DN, United Kingdom and School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL,
United Kingdom
| | - Paul L. A. Popelier
- Manchester Institute of Biotechnology (MIB), 131 Princess
Street, Manchester M1 7DN, United Kingdom and School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL,
United Kingdom
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13
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Thacker JCR, Wilson AL, Hughes ZE, Burn MJ, Maxwell PI, Popelier PLA. Towards the simulation of biomolecules: optimisation of peptide-capped glycine using FFLUX. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1431837] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Joseph C. R. Thacker
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
| | - Alex L. Wilson
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
| | - Zak E. Hughes
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
| | - Matthew J. Burn
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
| | - Peter I. Maxwell
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
| | - Paul L. A. Popelier
- Manchester Institute of Biotechnology (MIB) , Manchester, UK
- School of Chemistry, University of Manchester , Manchester, UK
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14
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Limas NG, Manz TA. Introducing DDEC6 atomic population analysis: part 4. Efficient parallel computation of net atomic charges, atomic spin moments, bond orders, and more. RSC Adv 2018; 8:2678-2707. [PMID: 35541489 PMCID: PMC9077577 DOI: 10.1039/c7ra11829e] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/13/2017] [Indexed: 01/03/2023] Open
Abstract
The DDEC6 method is one of the most accurate and broadly applicable atomic population analysis methods. It works for a broad range of periodic and non-periodic materials with no magnetism, collinear magnetism, and non-collinear magnetism irrespective of the basis set type. First, we show DDEC6 charge partitioning to assign net atomic charges corresponds to solving a series of 14 Lagrangians in order. Then, we provide flow diagrams for overall DDEC6 analysis, spin partitioning, and bond order calculations. We wrote an OpenMP parallelized Fortran code to provide efficient computations. We show that by storing large arrays as shared variables in cache line friendly order, memory requirements are independent of the number of parallel computing cores and false sharing is minimized. We show that both total memory required and the computational time scale linearly with increasing numbers of atoms in the unit cell. Using the presently chosen uniform grids, computational times of ∼9 to 94 seconds per atom were required to perform DDEC6 analysis on a single computing core in an Intel Xeon E5 multi-processor unit. Parallelization efficiencies were usually >50% for computations performed on 2 to 16 cores of a cache coherent node. As examples we study a B-DNA decamer, nickel metal, supercells of hexagonal ice crystals, six X@C60 endohedral fullerene complexes, a water dimer, a Mn12-acetate single molecule magnet exhibiting collinear magnetism, a Fe4O12N4C40H52 single molecule magnet exhibiting non-collinear magnetism, and several spin states of an ozone molecule. Efficient parallel computation was achieved for systems containing as few as one and as many as >8000 atoms in a unit cell. We varied many calculation factors (e.g., grid spacing, code design, thread arrangement, etc.) and report their effects on calculation speed and precision. We make recommendations for excellent performance. We parallelize the DDEC6 method to efficiently compute net atomic charges, atomic spin moments, and bond orders in diverse materials.![]()
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Affiliation(s)
- Nidia Gabaldon Limas
- Department of Chemical & Materials Engineering
- New Mexico State University
- Las Cruces
- USA
| | - Thomas A. Manz
- Department of Chemical & Materials Engineering
- New Mexico State University
- Las Cruces
- USA
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15
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McDonagh JL, Silva AF, Vincent MA, Popelier PLA. Machine Learning of Dynamic Electron Correlation Energies from Topological Atoms. J Chem Theory Comput 2017; 14:216-224. [PMID: 29211469 DOI: 10.1021/acs.jctc.7b01157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We present an innovative method for predicting the dynamic electron correlation energy of an atom or a bond in a molecule utilizing topological atoms. Our approach uses the machine learning method Kriging (Gaussian Process Regression with a non-zero mean function) to predict these dynamic electron correlation energy contributions. The true energy values are calculated by partitioning the MP2 two-particle density-matrix via the Interacting Quantum Atoms (IQA) procedure. To our knowledge, this is the first time such energies have been predicted by a machine learning technique. We present here three important proof-of-concept cases: the water monomer, the water dimer, and the van der Waals complex H2···He. These cases represent the final step toward the design of a full IQA potential for molecular simulation. This final piece will enable us to consider situations in which dispersion is the dominant intermolecular interaction. The results from these examples suggest a new method by which dispersion potentials for molecular simulation can be generated.
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Affiliation(s)
- James L McDonagh
- Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, Great Britain
| | - Arnaldo F Silva
- Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, Great Britain
| | - Mark A Vincent
- School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, Great Britain
| | - Paul L A Popelier
- Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, Great Britain.,School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, Great Britain
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16
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Maxwell PI, Popelier PLA. Unfavorable regions in the ramachandran plot: Is it really steric hindrance? The interacting quantum atoms perspective. J Comput Chem 2017; 38:2459-2474. [PMID: 28841241 PMCID: PMC5659141 DOI: 10.1002/jcc.24904] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/10/2017] [Accepted: 07/18/2017] [Indexed: 01/06/2023]
Abstract
Accurate description of the intrinsic preferences of amino acids is important to consider when developing a biomolecular force field. In this study, we use a modern energy partitioning approach called Interacting Quantum Atoms to inspect the cause of the φ and ψ torsional preferences of three dipeptides (Gly, Val, and Ile). Repeating energy trends at each of the molecular, functional group, and atomic levels are observed across both (1) the three amino acids and (2) the φ/ψ scans in Ramachandran plots. At the molecular level, it is surprisingly electrostatic destabilization that causes the high-energy regions in the Ramachandran plot, not molecular steric hindrance (related to the intra-atomic energy). At the functional group and atomic levels, the importance of key peptide atoms (Oi-1 , Ci , Ni , Ni+1 ) and some sidechain hydrogen atoms (Hγ ) are identified as responsible for the destabilization seen in the energetically disfavored Ramachandran regions. Consistently, the Oi-1 atoms are particularly important for the explanation of dipeptide intrinsic behavior, where electrostatic and steric destabilization unusually complement one another. The findings suggest that, at least for these dipeptides, it is the peptide group atoms that dominate the intrinsic behavior, more so than the sidechain atoms. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Peter I. Maxwell
- Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester M1 7DN, Great Britain and School of Chemistry, University of Manchester, Oxford RoadManchesterGreat BritainM13 9PL
| | - Paul L. A. Popelier
- Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester M1 7DN, Great Britain and School of Chemistry, University of Manchester, Oxford RoadManchesterGreat BritainM13 9PL
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17
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Geometry Optimization with Machine Trained Topological Atoms. Sci Rep 2017; 7:12817. [PMID: 28993674 PMCID: PMC5634454 DOI: 10.1038/s41598-017-12600-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/06/2017] [Indexed: 11/19/2022] Open
Abstract
The geometry optimization of a water molecule with a novel type of energy function called FFLUX is presented, which bypasses the traditional bonded potentials. Instead, topologically-partitioned atomic energies are trained by the machine learning method kriging to predict their IQA atomic energies for a previously unseen molecular geometry. Proof-of-concept that FFLUX’s architecture is suitable for geometry optimization is rigorously demonstrated. It is found that accurate kriging models can optimize 2000 distorted geometries to within 0.28 kJ mol−1 of the corresponding ab initio energy, and 50% of those to within 0.05 kJ mol−1. Kriging models are robust enough to optimize the molecular geometry to sub-noise accuracy, when two thirds of the geometric inputs are outside the training range of that model. Finally, the individual components of the potential energy are analyzed, and chemical intuition is reflected in the independent behavior of the three energy terms \documentclass[12pt]{minimal}
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\begin{document}$${E}_{{\rm{intra}}}^{{\rm{A}}}$$\end{document}EintraA(intra-atomic), \documentclass[12pt]{minimal}
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\begin{document}$${V}_{{\rm{x}}}^{\text{AA}\text{'}}$$\end{document}VxAA' (exchange), in contrast to standard force fields.
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18
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Maxwell PI, Popelier PLA. Accurate prediction of the energetics of weakly bound complexes using the machine learning method kriging. Struct Chem 2017. [DOI: 10.1007/s11224-017-0928-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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