1
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Hsu T, Sadigh B, Bulatov V, Zhou F. Score Dynamics: Scaling Molecular Dynamics with Picoseconds Time Steps via Conditional Diffusion Model. J Chem Theory Comput 2024; 20:2335-2348. [PMID: 38489243 DOI: 10.1021/acs.jctc.3c01361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
We propose score dynamics (SD), a general framework for learning accelerated evolution operators with large timesteps from molecular dynamics (MD) simulations. SD is centered around scores or derivatives of the transition log-probability with respect to the dynamical degrees of freedom. The latter play the same role as force fields in MD but are used in denoising diffusion probability models to generate discrete transitions of the dynamical variables in an SD time step, which can be orders of magnitude larger than a typical MD time step. In this work, we construct graph neural network-based SD models of realistic molecular systems that are evolved with 10 ps timesteps. We demonstrate the efficacy of SD with case studies of the alanine dipeptide and short alkanes in aqueous solution. Both equilibrium predictions derived from the stationary distributions of the conditional probability and kinetic predictions for the transition rates and transition paths are in good agreement with MD. Our current SD implementation is about 2 orders of magnitude faster than the MD counterpart for the systems studied in this work. Open challenges and possible future remedies to improve SD are also discussed.
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Affiliation(s)
- Tim Hsu
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Babak Sadigh
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Vasily Bulatov
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Fei Zhou
- Lawrence Livermore National Laboratory, Livermore, California 94551, United States
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2
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Jin J, Lee EK, Voth GA. Understanding dynamics in coarse-grained models. III. Roles of rotational motion and translation-rotation coupling in coarse-grained dynamics. J Chem Phys 2023; 159:164102. [PMID: 37870140 DOI: 10.1063/5.0167158] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/29/2023] [Indexed: 10/24/2023] Open
Abstract
This paper series aims to establish a complete correspondence between fine-grained (FG) and coarse-grained (CG) dynamics by way of excess entropy scaling (introduced in Paper I). While Paper II successfully captured translational motions in CG systems using a hard sphere mapping, the absence of rotational motions in single-site CG models introduces differences between FG and CG dynamics. In this third paper, our objective is to faithfully recover atomistic diffusion coefficients from CG dynamics by incorporating rotational dynamics. By extracting FG rotational diffusion, we unravel, for the first time reported to our knowledge, a universality in excess entropy scaling between the rotational and translational diffusion. Once the missing rotational dynamics are integrated into the CG translational dynamics, an effective translation-rotation coupling becomes essential. We propose two different approaches for estimating this coupling parameter: the rough hard sphere theory with acentric factor (temperature-independent) or the rough Lennard-Jones model with CG attractions (temperature-dependent). Altogether, we demonstrate that FG diffusion coefficients can be recovered from CG diffusion coefficients by (1) incorporating "entropy-free" rotational diffusion with translation-rotation coupling and (2) recapturing the missing entropy. Our findings shed light on the fundamental relationship between FG and CG dynamics in molecular fluids.
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Affiliation(s)
- Jaehyeok Jin
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Eok Kyun Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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3
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Chan KC, Li Z, Wenzel W. A Mori-Zwanzig Dissipative Particle Dynamics Approach for Anisotropic Coarse Grained Molecular Dynamics. J Chem Theory Comput 2023; 19:910-923. [PMID: 36645752 DOI: 10.1021/acs.jctc.2c00960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Coarse grained (CG) molecular dynamics simulations are widely used to accelerate atomistic simulations but generally lack a formalism to preserve the dynamics of the system. For spherical particles, the Mori-Zwanzig approach, while computationally complex, has ameliorated this problem. Here we present an anisotropic dissipative particle dynamics (ADPD) model as an extension of this approach, which accounts for the anisotropy for both conservative and nonconservative interactions. For a simple anisotropic system we parametrize the coarse grained force field representing ellipsoidal CG particles from the full-atomistic simulation. To represent the anisotropy of the system, both the conservative and dissipative terms are approximated using the Gay-Berne (GB) functional forms via a force-matching approach. We compare our model with other CG models and demonstrate that it yields better results in both static and dynamical properties. The inclusion of the anisotropic nonconservative force preserves the microscopic dynamical details, and hence the dynamical properties, such as diffusivity, can be better reproduced by the aspherical model. By generalizing the isotropic DPD model, this framework is effective and promising for the development of the CG model for polymers, macromolecules, and biological systems.
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Affiliation(s)
- Ka Chun Chan
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen76344, Germany
| | - Zhen Li
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina29634, United States
| | - Wolfgang Wenzel
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen76344, Germany
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4
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Klippenstein V, van der Vegt NFA. Bottom-Up Informed and Iteratively Optimized Coarse-Grained Non-Markovian Water Models with Accurate Dynamics. J Chem Theory Comput 2023; 19:1099-1110. [PMID: 36745567 PMCID: PMC9979609 DOI: 10.1021/acs.jctc.2c00871] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molecular dynamics (MD) simulations based on coarse-grained (CG) particle models of molecular liquids generally predict accelerated dynamics and misrepresent the time scales for molecular vibrations and diffusive motions. The parametrization of Generalized Langevin Equation (GLE) thermostats based on the microscopic dynamics of the fine-grained model provides a promising route to address this issue, in conjunction with the conservative interactions of the CG model obtained with standard coarse graining methods, such as iterative Boltzmann inversion, force matching, or relative entropy minimization. We report the application of a recently introduced bottom-up dynamic coarse graining method, based on the Mori-Zwanzig formalism, which provides accurate estimates of isotropic GLE memory kernels for several CG models of liquid water. We demonstrate that, with an additional iterative optimization of the memory kernels (IOMK) for the CG water models based on a practical iterative optimization technique, the velocity autocorrelation function of liquid water can be represented very accurately within a few iterations. By considering the distinct Van Hove function, we demonstrate that, with the presented methods, an accurate representation of structural relaxation can be achieved. We consider several distinct CG potentials to study how the choice of the CG potential affects the performance of bottom-up informed and iteratively optimized models.
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5
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Jin J, Schweizer KS, Voth GA. Understanding dynamics in coarse-grained models. II. Coarse-grained diffusion modeled using hard sphere theory. J Chem Phys 2023; 158:034104. [PMID: 36681632 DOI: 10.1063/5.0116300] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The first paper of this series [J. Chem. Phys. 158, 034103 (2023)] demonstrated that excess entropy scaling holds for both fine-grained and corresponding coarse-grained (CG) systems. Despite its universality, a more exact determination of the scaling relationship was not possible due to the semi-empirical nature. In this second paper, an analytical excess entropy scaling relation is derived for bottom-up CG systems. At the single-site CG resolution, effective hard sphere systems are constructed that yield near-identical dynamical properties as the target CG systems by taking advantage of how hard sphere dynamics and excess entropy can be analytically expressed in terms of the liquid packing fraction. Inspired by classical equilibrium perturbation theories and recent advances in constructing hard sphere models for predicting activated dynamics of supercooled liquids, we propose a new approach for understanding the diffusion of molecular liquids in the normal regime using hard sphere reference fluids. The proposed "fluctuation matching" is designed to have the same amplitude of long wavelength density fluctuations (dimensionless compressibility) as the CG system. Utilizing the Enskog theory to derive an expression for hard sphere diffusion coefficients, a bridge between the CG dynamics and excess entropy is then established. The CG diffusion coefficient can be roughly estimated using various equations of the state, and an accurate prediction of accelerated CG dynamics at different temperatures is also possible in advance of running any CG simulation. By introducing another layer of coarsening, these findings provide a more rigorous method to assess excess entropy scaling and understand the accelerated CG dynamics of molecular fluids.
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Affiliation(s)
- Jaehyeok Jin
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Kenneth S Schweizer
- Department of Material Science, Department of Chemistry, Department of Chemical and Biomolecular Engineering, and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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6
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Jin J, Schweizer KS, Voth GA. Understanding dynamics in coarse-grained models. I. Universal excess entropy scaling relationship. J Chem Phys 2023; 158:034103. [PMID: 36681649 DOI: 10.1063/5.0116299] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Coarse-grained (CG) models facilitate an efficient exploration of complex systems by reducing the unnecessary degrees of freedom of the fine-grained (FG) system while recapitulating major structural correlations. Unlike structural properties, assessing dynamic properties in CG modeling is often unfeasible due to the accelerated dynamics of the CG models, which allows for more efficient structural sampling. Therefore, the ultimate goal of the present series of articles is to establish a better correspondence between the FG and CG dynamics. To assess and compare dynamical properties in the FG and the corresponding CG models, we utilize the excess entropy scaling relationship. For Paper I of this series, we provide evidence that the FG and the corresponding CG counterpart follow the same universal scaling relationship. By carefully reviewing and examining the literature, we develop a new theory to calculate excess entropies for the FG and CG systems while accounting for entropy representability. We demonstrate that the excess entropy scaling idea can be readily applied to liquid water and methanol systems at both the FG and CG resolutions. For both liquids, we reveal that the scaling exponents remain unchanged from the coarse-graining process, indicating that the scaling behavior is universal for the same underlying molecular systems. Combining this finding with the concept of mapping entropy in CG models, we show that the missing entropy plays an important role in accelerating the CG dynamics.
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Affiliation(s)
- Jaehyeok Jin
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Kenneth S Schweizer
- Department of Material Science, Department of Chemistry, Department of Chemical and Biomolecular Engineering, and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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7
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Schmid F. Understanding and Modeling Polymers: The Challenge of Multiple Scales. ACS POLYMERS AU 2022. [DOI: 10.1021/acspolymersau.2c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Friederike Schmid
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 9, 55128Mainz, Germany
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8
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Jin J, Pak AJ, Durumeric AEP, Loose TD, Voth GA. Bottom-up Coarse-Graining: Principles and Perspectives. J Chem Theory Comput 2022; 18:5759-5791. [PMID: 36070494 PMCID: PMC9558379 DOI: 10.1021/acs.jctc.2c00643] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Indexed: 01/14/2023]
Abstract
Large-scale computational molecular models provide scientists a means to investigate the effect of microscopic details on emergent mesoscopic behavior. Elucidating the relationship between variations on the molecular scale and macroscopic observable properties facilitates an understanding of the molecular interactions driving the properties of real world materials and complex systems (e.g., those found in biology, chemistry, and materials science). As a result, discovering an explicit, systematic connection between microscopic nature and emergent mesoscopic behavior is a fundamental goal for this type of investigation. The molecular forces critical to driving the behavior of complex heterogeneous systems are often unclear. More problematically, simulations of representative model systems are often prohibitively expensive from both spatial and temporal perspectives, impeding straightforward investigations over possible hypotheses characterizing molecular behavior. While the reduction in resolution of a study, such as moving from an atomistic simulation to that of the resolution of large coarse-grained (CG) groups of atoms, can partially ameliorate the cost of individual simulations, the relationship between the proposed microscopic details and this intermediate resolution is nontrivial and presents new obstacles to study. Small portions of these complex systems can be realistically simulated. Alone, these smaller simulations likely do not provide insight into collectively emergent behavior. However, by proposing that the driving forces in both smaller and larger systems (containing many related copies of the smaller system) have an explicit connection, systematic bottom-up CG techniques can be used to transfer CG hypotheses discovered using a smaller scale system to a larger system of primary interest. The proposed connection between different CG systems is prescribed by (i) the CG representation (mapping) and (ii) the functional form and parameters used to represent the CG energetics, which approximate potentials of mean force (PMFs). As a result, the design of CG methods that facilitate a variety of physically relevant representations, approximations, and force fields is critical to moving the frontier of systematic CG forward. Crucially, the proposed connection between the system used for parametrization and the system of interest is orthogonal to the optimization used to approximate the potential of mean force present in all systematic CG methods. The empirical efficacy of machine learning techniques on a variety of tasks provides strong motivation to consider these approaches for approximating the PMF and analyzing these approximations.
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Affiliation(s)
- Jaehyeok Jin
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Alexander J. Pak
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Aleksander E. P. Durumeric
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Timothy D. Loose
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory A. Voth
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
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9
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Suárez-López R, Puntes VF, Bastús NG, Hervés C, Jaime C. Nucleation and growth of gold nanoparticles in the presence of different surfactants. A dissipative particle dynamics study. Sci Rep 2022; 12:13926. [PMID: 35977997 PMCID: PMC9385746 DOI: 10.1038/s41598-022-18155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 08/05/2022] [Indexed: 11/23/2022] Open
Abstract
Nanoparticles (NPs) show promising applications in biomedicine, catalysis, and energy harvesting. This applicability relies on controlling the material’s features at the nanometer scale. Surfactants, a unique class of surface-active molecules, have a remarkable ability to tune NPs activity; provide specific functions, avoid their aggregation, and create stable colloidal solutions. Surfactants also control nanoparticles’ nucleation and growth processes by modifying nuclei solubility and surface energy. While nucleation seems independent from the surfactant, NP’s growth depends on it. NP`s size is influenced by the type of functional group (C, O, S or N), length of its C chain and NP to surfactant ratio. In this paper, gold nanoparticles (Au NPs) are taken as model systems to study how nucleation and growth processes are affected by the choice of surfactants by Dissipative Particle Dynamics (DPD) simulations. DPD has been mainly used for studying biochemical structures, like lipid bilayer models. However, the study of solid NPs, and their conjugates, needs the introduction of a new metallic component. To represent the collective phenomena of these large systems, their degrees of freedom are reduced by Coarse-Grained (CG) models. DPD behaved as a powerful tool for studying complex systems and shedding some light on some experimental observations, otherwise difficult to explain.
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Affiliation(s)
- Rosa Suárez-López
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Barcelona, Spain
| | - Víctor F Puntes
- Institut Català de Nanociència i Nanotecnologia (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain.,Vall d'Hebron Institut de Recerca (VHIR), 08035, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), P. Lluís Companys 23, 08010, Barcelona, Spain
| | - Neus G Bastús
- Institut Català de Nanociència i Nanotecnologia (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Carmen Hervés
- Institut Català de Nanociència i Nanotecnologia (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Carlos Jaime
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Barcelona, Spain.
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10
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Markutsya S, Haley A, Gordon MS. Coarse-Grained Water Model Development for Accurate Dynamics and Structure Prediction. ACS OMEGA 2022; 7:25898-25904. [PMID: 35910114 PMCID: PMC9330847 DOI: 10.1021/acsomega.2c03857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Several coarse-graining (CG) methods have been combined to develop a CG model of water capable of the accurate prediction of structure and dynamics properties. The multiscale coarse-graining (MS-CG) method based on force matching and the PDF-based coarse-graining method were used for accurate dynamics prediction. The iterative Boltzmann inversion (IBI) method was added for accurate structure representation. The approach is applied to bulk water, and the results show close reproduction of the CG structure when compared with the reference atomistic data. The combination of MS-CG and IBI methods facilitates the development of CG force fields at different temperatures based on a single MS-CG coarse-graining procedure. The dynamic properties of the CG water model closely match those obtained from the reference atomistic system. The general application of this approach to any existing coarse-graining methods is discussed.
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Affiliation(s)
- Sergiy Markutsya
- Department
of Mechanical Engineering, University of
Kentucky, Paducah, Kentucky 42001, United States
| | - Austin Haley
- Department
of Mechanical Engineering, University of
Kentucky, Paducah, Kentucky 42001, United States
| | - Mark S. Gordon
- Department
of Chemistry and Ames Laboratory, Iowa State
University, Ames, Iowa 50011, United States
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11
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Klippenstein V, van der Vegt N. Cross-Correlation Corrected Friction in Generalized Langevin Models: Application to the continuous Asakura-Oosawa Model. J Chem Phys 2022; 157:044103. [DOI: 10.1063/5.0093056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a previous study we proposed a method to parameterize isotropic, configuration independent, non-Markovian generalized Langevin thermostats to achieve dynamic consistency in coarse-grained models. In the current study, by applying the same strategy, we develop coarse-grained implicit solvent models for the continuous Asakura-Oosawa model, which under certain conditions allows to develop very accurate coarse-grained potentials. By developing coarse-grained models for different reference systems with varying parameters, we test the broader applicability of the proposed procedure and demonstrate the relevance of accurate coarse-grained potentials in bottom-up derived dissipative models. We study how different system parameters affect the dynamic representability of the coarse-grained models. In particular we find that the quality of the coarse-grained potential is crucial to correctly model the backscattering effect due to collisions on the coarse-grained scale. In the dynamics of colloid suspensions the hydrodynamic interactions affect the long-time scale dynamics by solvent mediated momentum transfer. These interactions are not explicitly modeled in the presented coarse-grained models, which poses some limitations to the proposed coarse-graining scheme. The Asakura-Oosawa model allows a tuning of system parameters, to gain an improved understanding of these limitations. We also propose three new iterative optimization schemes to fine tune the generalized Langevin thermostat to exactly match the reference velocity-autocorrelation function.
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Affiliation(s)
| | - Nico van der Vegt
- Chemistry, Technische Universität Darmstadt Fachbereich Chemie, Germany
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12
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Stoffel TD, Haskins JB, Lawson JW, Markutsya S. Coarse-Grained Dynamically Accurate Simulations of Ionic Liquids: [pyr14][TFSI] and [EMIM][BF 4]. J Phys Chem B 2022; 126:1819-1829. [PMID: 35171594 DOI: 10.1021/acs.jpcb.1c08107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, coarse-grained (CG) models for two different sets of ionic liquids were developed from atomistic molecular dynamics (MD) reference systems, expanding their system size and time duration capabilities. The bonded force field of the CG systems was built using harmonic oscillator potential (HOP) fitting, while the nonbonded force field was generated with the multiscale coarse-graining (MS-CG) approach based on force matching. The dynamics of each system were corrected using the probability distribution function-based coarse-grained molecular dynamics (PDF-based CGMD) method. The structure and dynamics of each system were proven to match reference system data at two temperature scales. CG models and force fields for these liquids were developed to exemplify a general purpose methodology for producing MD results of ionic liquids and other fluids with accurate structural as well as dynamic properties. As an application, developed ionic liquids CG models were then applied to study vacuum-interface interaction. Density profile results of vacuum-interface exposure show significant deviation from bulk behavior. At the interface, multilayer ordering of ionic liquids is predicted to be similar to those observed from an experimental work. This ordering is intensified by decreasing temperature and use of the PDF-based CGMD method as opposed to conventional CG methods.
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Affiliation(s)
- Tyler D Stoffel
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Justin B Haskins
- Thermal Protections Branch, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - John W Lawson
- Intelligent Systems Division, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - Sergiy Markutsya
- Department of Mechanical Engineering, University of Kentucky, Paducah, Kentucky 42001, United States
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13
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14
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Santo KP, Neimark AV. Dissipative particle dynamics simulations in colloid and Interface science: a review. Adv Colloid Interface Sci 2021; 298:102545. [PMID: 34757286 DOI: 10.1016/j.cis.2021.102545] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 12/31/2022]
Abstract
Dissipative particle dynamics (DPD) is one of the most efficient mesoscale coarse-grained methodologies for modeling soft matter systems. Here, we comprehensively review the progress in theoretical formulations, parametrization strategies, and applications of DPD over the last two decades. DPD bridges the gap between the microscopic atomistic and macroscopic continuum length and time scales. Numerous efforts have been performed to improve the computational efficiency and to develop advanced versions and modifications of the original DPD framework. The progress in the parametrization techniques that can reproduce the engineering properties of experimental systems attracted a lot of interest from the industrial community longing to use DPD to characterize, help design and optimize the practical products. While there are still areas for improvements, DPD has been efficiently applied to numerous colloidal and interfacial phenomena involving phase separations, self-assembly, and transport in polymeric, surfactant, nanoparticle, and biomolecules systems.
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Affiliation(s)
- Kolattukudy P Santo
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, United States
| | - Alexander V Neimark
- Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, United States.
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15
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Dhamankar S, Webb MA. Chemically specific coarse‐graining of polymers: Methods and prospects. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210555] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Satyen Dhamankar
- Department of Chemical and Biological Engineering Princeton University Princeton New Jersey USA
| | - Michael A. Webb
- Department of Chemical and Biological Engineering Princeton University Princeton New Jersey USA
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16
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Izvekov S. Mori-Zwanzig projection operator formalism: Particle-based coarse-grained dynamics of open classical systems far from equilibrium. Phys Rev E 2021; 104:024121. [PMID: 34525637 DOI: 10.1103/physreve.104.024121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/20/2021] [Indexed: 11/07/2022]
Abstract
We present a generalized Langevin equation (GLE) of motion that governs exactly the time evolution of phase-space observables in finite open systems described by classical Hamiltonians with explicitly time-dependent potentials. This formalism is based on the Mori-Zwanzig projection operator (PO) method with a time-independent Zwanzig PO within a Heisenberg (Lagrangian) picture and reduced description of Hamiltonian systems in terms of canonical relevant and irrelevant coordinates. We demonstrate that, similarly to closed systems, GLE dynamics in Hamiltonian systems in the presence of time-dependent potentials is determined by conservative, dissipative memory, and projected force fields, and that the memory functions relate to the projected force, which is a two-time process, in a way that is reminiscent of the equilibrium second fluctuation-dissipation relation. We further show that, in the most general case, the memory kernel depends on the relevant momentum gradients of the (Boltzmann) entropy of the irrelevant subsystem. Using two Zwanzig operators which are, respectively, functionals of the canonical and generalized canonical probability densities, we then derive what we call canonical and generalized canonical GLEs. Further, we can formulate the particle-based, coarse-grained (CG) GLE dynamics by transitioning to Jacobi coordinates which corresponds to a particle set partitioning of the Hamiltonian system. The obtained canonical CG GLE of motion for the relevant momenta is a generalization of the CG equation of motion known for closed systems. Also, using a Markovian approximation of the canonical CG GLE, we can extend the dissipative particle dynamics equation to open systems. A distinctive feature of our extension is a use of explicitly time-dependent frictions, which reflect the changes in the dissipation rate caused by time-dependent coupling to an external bath. Our GLE formalism and workflow constitute a general and viable framework that can be readily used as a starting point to rigorously formulate microscopically informed CG treatments for a variety of phenomena in externally forced systems far from equilibrium.
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Affiliation(s)
- Sergei Izvekov
- Weapons and Materials Research Directorate, U.S. Army DEVCOM Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA
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17
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Klippenstein V, Tripathy M, Jung G, Schmid F, van der Vegt NFA. Introducing Memory in Coarse-Grained Molecular Simulations. J Phys Chem B 2021; 125:4931-4954. [PMID: 33982567 PMCID: PMC8154603 DOI: 10.1021/acs.jpcb.1c01120] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Preserving the correct dynamics at the coarse-grained (CG) level is a pressing problem in the development of systematic CG models in soft matter simulation. Starting from the seminal idea of simple time-scale mapping, there have been many efforts over the years toward establishing a meticulous connection between the CG and fine-grained (FG) dynamics based on fundamental statistical mechanics approaches. One of the most successful attempts in this context has been the development of CG models based on the Mori-Zwanzig (MZ) theory, where the resulting equation of motion has the form of a generalized Langevin equation (GLE) and closely preserves the underlying FG dynamics. In this Review, we describe some of the recent studies in this regard. We focus on the construction and simulation of dynamically consistent systematic CG models based on the GLE, both in the simple Markovian limit and the non-Markovian case. Some recent studies of physical effects of memory are also discussed. The Review is aimed at summarizing recent developments in the field while highlighting the major challenges and possible future directions.
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Affiliation(s)
- Viktor Klippenstein
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Madhusmita Tripathy
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Gerhard Jung
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21 A, A-6020 Innsbruck, Austria
| | - Friederike Schmid
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 9, 55128 Mainz, Germany
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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Han Y, Jin J, Voth GA. Constructing many-body dissipative particle dynamics models of fluids from bottom-up coarse-graining. J Chem Phys 2021; 154:084122. [PMID: 33639745 DOI: 10.1063/5.0035184] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Since their emergence in the 1990s, mesoscopic models of fluids have been widely used to study complex organization and transport phenomena beyond the molecular scale. Even though these models are designed based on results from physics at the meso- and macroscale, such as fluid mechanics and statistical field theory, the underlying microscopic foundation of these models is not as well defined. This paper aims to build such a systematic connection using bottom-up coarse-graining methods. From the recently developed dynamic coarse-graining scheme, we introduce a statistical inference framework of explicit many-body conservative interaction that quantitatively recapitulates the mesoscopic structure of the underlying fluid. To further consider the dissipative and fluctuation forces, we design a novel algorithm that parameterizes these forces. By utilizing this algorithm, we derive pairwise decomposable friction kernels under both non-Markovian and Markovian limits where both short- and long-time features of the coarse-grained dynamics are reproduced. Finally, through these new developments, the many-body dissipative particle dynamics type of equations of motion are successfully derived. The methodologies developed in this work thus open a new avenue for the construction of direct bottom-up mesoscopic models that naturally bridge the meso- and macroscopic physics.
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Affiliation(s)
- Yining Han
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Jaehyeok Jin
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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Zhao L, Li Z, Wang Z, Caswell B, Ouyang J, Karniadakis GE. Active- and transfer-learning applied to microscale-macroscale coupling to simulate viscoelastic flows. JOURNAL OF COMPUTATIONAL PHYSICS 2021; 427:110069. [DOI: 10.1016/j.jcp.2020.110069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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20
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Tanis I, Rousseau B, Soulard L, Lemarchand CA. Assessment of an anisotropic coarse-grained model for cis-1,4-polybutadiene: a bottom-up approach. SOFT MATTER 2021; 17:621-636. [PMID: 33206108 DOI: 10.1039/d0sm01572e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The spherical representation usually utilized for the coarse-grained particles of soft matter systems is an assumption and pertinent studies have shown that both structural and dynamical properties can depend on anisotropic effects. On these grounds, we develop coarse-grained equations of motion which take into account explicitly the anisotropy of the beads. As a first step, this model incorporates only conservative terms. Inclusion of the dissipative and random terms is in principle possible but is beyond the scope of this study. The translational dynamics of the beads is tracked using the position and momentum of their center of mass, while their rotational dynamics is modeled by representing their orientation through the use of quaternions, similarly to the case of rigid bodies. The associated force and torque controlling the motion are derived from atomistic molecular dynamics (MD) simulations via a bottom-up approach and define a coarse-grained potential. The assumptions of the model are clearly stated and checked for a reference system of a cis-1,4-polybutadiene melt. In particular, the choice of the angular velocity as a slow variable is justified by comparing its dynamics to atomic vibrations. The accuracy of this approach to reproduce static structural features of the polymer melt is assessed.
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Affiliation(s)
| | - Bernard Rousseau
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR 8000, 91405 Orsay, France
| | - Laurent Soulard
- CEA, DAM, DIF, 91297 Arpajon Cedex, France. and Université Paris-Saclay, CEA, Laboratoire Matière sous Conditions Extrêmes, 91680, Bruyères-le-Châtel, France
| | - Claire A Lemarchand
- CEA, DAM, DIF, 91297 Arpajon Cedex, France. and Université Paris-Saclay, CEA, Laboratoire Matière sous Conditions Extrêmes, 91680, Bruyères-le-Châtel, France
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21
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Delle Site L, Praprotnik M, Bell JB, Klein R. Particle–Continuum Coupling and its Scaling Regimes: Theory and Applications. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.201900232] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Luigi Delle Site
- Freie Universität Berlin Institute of Mathematics Arnimallee 6, 14195 Berlin Germany
| | - Matej Praprotnik
- Laboratory for Molecular Modeling National Institute of Chemistry SI‐1001 Ljubljana, Slovenia & Department of Physics Faculty of Mathematics and Physics University of Ljubljana SI‐1000 Ljubljana Slovenia
| | - John B. Bell
- Lawrence Berkeley National Lab 1 Cyclotron Rd. Berkeley CA 94720 USA
| | - Rupert Klein
- Freie Universität Berlin Institute of Mathematics Arnimallee 6, 14195 Berlin Germany
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22
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Müller M. Process-directed self-assembly of copolymers: Results of and challenges for simulation studies. Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2019.101198] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Wang S, Li X, Gong X, Liang H. Mechanistic modeling of spontaneous penetration of carbon nanocones into membrane vesicles. NANOSCALE 2020; 12:2686-2694. [PMID: 31916567 DOI: 10.1039/c9nr09098c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Carbon nanocones (CNCs) are promising drug delivery systems that can be functionalized with a variety of biomolecules (such as proteins, peptides, or antibodies), which allow for site-specific, targeted payload delivery to particular cells and organs. However, considerable uncertainty exists with respect to the toxicity of CNCs on their conical shape, and the underlying mechanism that leads to the penetration of CNCs (especially the truncated ones) in and through the cell membrane is not yet well understood. Using a coarse-grained dissipative particle dynamics method, we systematically investigate the spontaneous penetration of untruncated and truncated CNCs into membrane vesicles. For untruncated CNCs, the simulation results show that both pristine and oxidized ones can spontaneously penetrate across or be attached to the vesicle surface without membrane rupture, indicating low or insignificant toxicity. However, for truncated CNCs, we find that both the apex angle and aspect ratio can influence the CNC-membrane interactions and CNC-induced toxicity: a higher apex angle (and/or a lower aspect ratio) yields a higher toxicity of truncated CNCs. Further free energy analysis reveals that the lowest free energy path during the penetration is associated with CNC's orientation and rotation. For a truncated CNC with a low aspect ratio and high apex angle, it tends to rotate itself to a preferred standing-up fashion inside the vesicle membrane, posing an enhanced toxicity of CNCs. These findings may provide useful guidelines for designing effective CNC vehicles for drug delivery.
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Affiliation(s)
- Shuo Wang
- Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering (State Key Laboratory of Ocean Engineering, MOE Key Laboratory of Hydrodynamics), Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou 310027, P. R. China.
| | - Xiaobo Gong
- Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering (State Key Laboratory of Ocean Engineering, MOE Key Laboratory of Hydrodynamics), Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Haojun Liang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China and Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China
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Vaiwala R, Jadhav S, Thaokar R. Establishing an Electrostatics Paradigm for Membrane Electroporation in the Framework of Dissipative Particle Dynamics. J Chem Theory Comput 2019; 15:5737-5749. [PMID: 31430431 DOI: 10.1021/acs.jctc.9b00573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With an exclusive aim to looking into a mechanism of membrane electroporation on mesoscopic length and time scales, we report the dissipative particle dynamics (DPD) simulation results for systems with and without electrolytes. A polarizable DPD model of water is employed for accurate modeling of long-range electrostatics near the water-lipid interfaces. A great deal of discussion on field induced change in dipole moments of water and lipids together with the special variation of electric field is made in order to understand the dielectrophoretic movement of water, initiating a pore formation via an intrusion through the bilayer core. The presence of salt alters the dipolar arrangement of lipids and water, and thereby it reduces the external field required to create a pore in the membrane. The species fluxes through the pore, distributions for bead density, electrostatic potential, stresses across the membrane, etc. are used to answer some of the key questions pertaining to mechanism of electroporation. The findings are compared with the molecular dynamics simulation results found in the literature, and the comparison successfully establishes an electrostatics paradigm for biomembrane studies using DPD simulations.
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Affiliation(s)
- Rakesh Vaiwala
- Department of Chemical Engineering , Indian Institute of Technology Bombay , Mumbai 400 076 , India
| | - Sameer Jadhav
- Department of Chemical Engineering , Indian Institute of Technology Bombay , Mumbai 400 076 , India
| | - Rochish Thaokar
- Department of Chemical Engineering , Indian Institute of Technology Bombay , Mumbai 400 076 , India
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25
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Recent Progress towards Chemically-Specific Coarse-Grained Simulation Models with Consistent Dynamical Properties. COMPUTATION 2019. [DOI: 10.3390/computation7030042] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Coarse-grained (CG) models can provide computationally efficient and conceptually simple characterizations of soft matter systems. While generic models probe the underlying physics governing an entire family of free-energy landscapes, bottom-up CG models are systematically constructed from a higher-resolution model to retain a high level of chemical specificity. The removal of degrees of freedom from the system modifies the relationship between the relative time scales of distinct dynamical processes through both a loss of friction and a “smoothing” of the free-energy landscape. While these effects typically result in faster dynamics, decreasing the computational expense of the model, they also obscure the connection to the true dynamics of the system. The lack of consistent dynamics is a serious limitation for CG models, which not only prevents quantitatively accurate predictions of dynamical observables but can also lead to qualitatively incorrect descriptions of the characteristic dynamical processes. With many methods available for optimizing the structural and thermodynamic properties of chemically-specific CG models, recent years have seen a stark increase in investigations addressing the accurate description of dynamical properties generated from CG simulations. In this review, we present an overview of these efforts, ranging from bottom-up parameterizations of generalized Langevin equations to refinements of the CG force field based on a Markov state modeling framework. We aim to make connections between seemingly disparate approaches, while laying out some of the major challenges as well as potential directions for future efforts.
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26
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Zavadlav J, Marrink SJ, Praprotnik M. SWINGER: a clustering algorithm for concurrent coupling of atomistic and supramolecular liquids. Interface Focus 2019; 9:20180075. [PMID: 31065343 PMCID: PMC6501350 DOI: 10.1098/rsfs.2018.0075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2019] [Indexed: 12/11/2022] Open
Abstract
In this contribution, we review recent developments and applications of a dynamic clustering algorithm SWINGER tailored for the multiscale molecular simulations of biomolecular systems. The algorithm on-the-fly redistributes solvent molecules among supramolecular clusters. In particular, we focus on its applications in combination with the adaptive resolution scheme, which concurrently couples atomistic and coarse-grained molecular representations. We showcase the versatility of our multiscale approach on a few applications to biomolecular systems coupling atomistic and supramolecular water models such as the well-established MARTINI and dissipative particle dynamics models and provide an outlook for future work.
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Affiliation(s)
- Julija Zavadlav
- Computational Science and Engineering Laboratory, ETH-Zurich, Clausiusstrasse 33, 8092 Zurich, Switzerland
| | - Siewert J. Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747, AG Groningen, The Netherlands
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
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27
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Friederich P, Fediai A, Kaiser S, Konrad M, Jung N, Wenzel W. Toward Design of Novel Materials for Organic Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1808256. [PMID: 31012166 DOI: 10.1002/adma.201808256] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Indexed: 06/09/2023]
Abstract
Materials for organic electronics are presently used in prominent applications, such as displays in mobile devices, while being intensely researched for other purposes, such as organic photovoltaics, large-area devices, and thin-film transistors. Many of the challenges to improve and optimize these applications are material related and there is a nearly infinite chemical space that needs to be explored to identify the most suitable material candidates. Established experimental approaches struggle with the size and complexity of this chemical space. Herein, the development of simulation methods is addressed, with a particular emphasis on predictive multiscale protocols, to complement experimental research in the identification of novel materials and illustrate the potential of these methods with a few prominent recent applications. Finally, the potential of machine learning and methods based on artificial intelligence is discussed to further accelerate the search for new materials.
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Affiliation(s)
- Pascal Friederich
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Department of Chemistry, University of Toronto, 80 St. George Street, M5S 3H6, Toronto, Ontario, Canada
| | - Artem Fediai
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Simon Kaiser
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Manuel Konrad
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Nicole Jung
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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28
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Wang Y, Li Z, Xu J, Yang C, Karniadakis GE. Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces. SOFT MATTER 2019; 15:1747-1757. [PMID: 30672954 PMCID: PMC6414210 DOI: 10.1039/c8sm02170h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We develop an efficient parallel multiscale method that bridges the atomistic and mesoscale regimes, from nanometers to microns and beyond, via concurrent coupling of atomistic simulation and mesoscopic dynamics. In particular, we combine an all-atom molecular dynamics (MD) description for specific atomistic details in the vicinity of the functional surface with a dissipative particle dynamics (DPD) approach that captures mesoscopic hydrodynamics in the domain away from the functional surface. In order to achieve a seamless transition in dynamic properties we endow the MD simulation with a DPD thermostat, which is validated against experimental results by modeling water at different temperatures. We then validate the MD-DPD coupling method for transient Couette and Poiseuille flows, demonstrating that the concurrent MD-DPD coupling can resolve accurately the continuum-based analytical solutions. Subsequently, we simulate shear flows over grafted polydimethylsiloxane (PDMS) surfaces (polymer brushes) for various grafting densities, and investigate the slip flow as a function of the shear stress. We verify that a "universal" power law exists for the slip length, in agreement with published results. Having validated the MD-DPD coupling method, we simulate time-dependent flows past an endothelial glycocalyx layer (EGL) in a microchannel. Coupled simulation results elucidate the dynamics of the EGL changing from an equilibrium state to a compressed state under shear by aligning the molecular structures along the shear direction. MD-DPD simulation results agree well with results of a single MD simulation, but with the former more than two orders of magnitude faster than the latter for system sizes above one micron.
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Affiliation(s)
- Yuying Wang
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Li
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
| | - Junbo Xu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Yang
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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29
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Deichmann G, van der Vegt NFA. Bottom-up approach to represent dynamic properties in coarse-grained molecular simulations. J Chem Phys 2019; 149:244114. [PMID: 30599732 DOI: 10.1063/1.5064369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several molecular coarse-graining methods have been proposed in recent years to derive chemical- and state-point transferable force fields. While these force fields describe structural and thermodynamic properties in good agreement with fine-grained models and experiments, dynamic properties are usually overestimated. Herein, we examine if the long-time dynamic properties of molecular coarse-grained (CG) systems can be correctly represented by employing a dissipative particle dynamics (DPD) thermostat, which is "bottom-up informed" by means of a variant of the Markovian Mori-Zwanzig (MZ) DPD coarse-graining method. We report single-site and multiple-site CG models for a monomer, dimer, and 24mer based on 2,2-dimethyl propane as a chemical repeat unit and report data obtained from MZ-DPD simulations of liquids, polymer solutions, and polymer melts. We find that despite incomplete time scale separation of the molecular CG model, MZ-DPD achieves quantitative accuracy in predicting diffusive dynamics in single-component liquids and polymer solutions (24mers in a dimer solvent). We also find that MZ-DPD simulations of molecular penetrant diffusion in polymer networks do not reach quantitative agreement with the fine-grained model. Modeling diffusion governed by the activated barrier crossing of small molecular penetrants in these dense systems requires an accurate description of energy barriers, presumably combined with the treatment of memory effects. The use of a MZ-DPD thermostat extends the scope and applicability of molecular CG models for multicomponent systems where a correct description of the relative diffusion rates of the different components is important.
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Affiliation(s)
- Gregor Deichmann
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
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30
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Di Pasquale N, Hudson T, Icardi M. Systematic derivation of hybrid coarse-grained models. Phys Rev E 2019; 99:013303. [PMID: 30780282 DOI: 10.1103/physreve.99.013303] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Indexed: 06/09/2023]
Abstract
Molecular dynamics represents a key enabling technology for applications ranging from biology to the development of new materials. However, many real-world applications remain inaccessible to fully resolved simulations due to their unsustainable computational costs and must therefore rely on semiempirical coarse-grained models. Significant efforts have been devoted in the last decade towards improving the predictivity of these coarse-grained models and providing a rigorous justification of their use, through a combination of theoretical studies and data-driven approaches. One of the most promising research efforts is the (re)discovery of the Mori-Zwanzig projection as a generic, yet systematic, theoretical tool for deriving coarse-grained models. Despite its clean mathematical formulation and generality, there are still many open questions about its applicability and assumptions. In this work, we propose a detailed derivation of a hybrid multiscale system, generalizing and further investigating the approach developed in Español [Europhys. Lett. 88, 40008 (2009)10.1209/0295-5075/88/40008]. Issues such as the general coexistence of atoms (fully resolved degrees of freedom) and beads (larger coarse-grained units), the role of the fine-to-coarse mapping chosen, and the approximation of effective potentials are discussed. The theoretical discussion is supported by numerical simulations of a monodimensional nonlinear periodic benchmark system with an open-source parallel Julia code, easily extensible to arbitrary potential models and fine-to-coarse mapping functions. The results presented highlight the importance of introducing, in the macroscopic model, nonconstant fluctuating and dissipative terms, given by the Mori-Zwanzig approach, to correctly reproduce the reference fine-grained results, without requiring ad hoc calibration of interaction potentials and thermostats.
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Affiliation(s)
- Nicodemo Di Pasquale
- Department of Mathematics, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Thomas Hudson
- Warwick Mathematics Institute, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Matteo Icardi
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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31
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Han Y, Dama JF, Voth GA. Mesoscopic coarse-grained representations of fluids rigorously derived from atomistic models. J Chem Phys 2018; 149:044104. [DOI: 10.1063/1.5039738] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Yining Han
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - James F. Dama
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory A. Voth
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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32
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Kim KS, Han MH, Kim C, Li Z, Karniadakis GE, Lee EK. Nature of intrinsic uncertainties in equilibrium molecular dynamics estimation of shear viscosity for simple and complex fluids. J Chem Phys 2018; 149:044510. [DOI: 10.1063/1.5035119] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kang-Sahn Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Myung Hoon Han
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Changho Kim
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Applied Mathematics, University of California, Merced, California 95343, USA
| | - Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Eok Kyun Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
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33
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Zavadlav J, Praprotnik M. Adaptive resolution simulations coupling atomistic water to dissipative particle dynamics. J Chem Phys 2018; 147:114110. [PMID: 28938807 DOI: 10.1063/1.4986916] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Multiscale methods are the most efficient way to address the interlinked spatiotemporal scales encountered in soft matter and molecular liquids. In the literature reported hybrid approaches span from quantum to atomistic, coarse-grained, and continuum length scales. In this article, we present the hybrid coupling of the molecular dynamics (MD) and dissipative particle dynamics (DPD) methods, bridging the micro- and mesoscopic descriptions. The interfacing is performed within the adaptive resolution scheme (AdResS), which is a linear momentum conserving coupling technique. Our methodology is hence suitable to simulate fluids on the micro/mesoscopic scale, where hydrodynamics plays an important role. The presented approach is showcased for water at ambient conditions. The supramolecular coupling is enabled by a recently developed clustering algorithm SWINGER that assembles, disassembles, and reassembles clusters as needed during the course of the simulation. This allows for a seamless coupling between standard atomistic MD and DPD models. The developed framework can be readily applied to various applications in the fields of materials and life sciences, e.g., simulations of phospholipids and polymer melts, or to study the red blood cells behavior in normal and disease states.
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Affiliation(s)
- Julija Zavadlav
- Chair of Computational Science, ETH Zürich, Clausiusstrasse 33, CH-8092 Zurich, Switzerland
| | - Matej Praprotnik
- Department of Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
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34
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Mukherjee B, Peter C, Kremer K. Single molecule translocation in smectics illustrates the challenge for time-mapping in simulations on multiple scales. J Chem Phys 2018; 147:114501. [PMID: 28938812 DOI: 10.1063/1.5001482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Understanding the connections between the characteristic dynamical time scales associated with a coarse-grained (CG) and a detailed representation is central to the applicability of the coarse-graining methods to understand molecular processes. The process of coarse graining leads to an accelerated dynamics, owing to the smoothening of the underlying free-energy landscapes. Often a single time-mapping factor is used to relate the time scales associated with the two representations. We critically examine this idea using a model system ideally suited for this purpose. Single molecular transport properties are studied via molecular dynamics simulations of the CG and atomistic representations of a liquid crystalline, azobenzene containing mesogen, simulated in the smectic and the isotropic phases. The out-of-plane dynamics in the smectic phase occurs via molecular hops from one smectic layer to the next. Hopping can occur via two mechanisms, with and without significant reorientation. The out-of-plane transport can be understood as a superposition of two (one associated with each mode of transport) independent continuous time random walks for which a single time-mapping factor would be rather inadequate. A comparison of the free-energy surfaces, relevant to the out-of-plane transport, qualitatively supports the above observations. Thus, this work underlines the need for building CG models that exhibit both structural and dynamical consistency to the underlying atomistic model.
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Affiliation(s)
| | - Christine Peter
- Department of Chemistry, University of Konstanz, 78547 Konstanz, Germany
| | - Kurt Kremer
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
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Vaiwala R, Jadhav S, Thaokar R. Electrostatic interactions in dissipative particle dynamics-Ewald-like formalism, error analysis, and pressure computation. J Chem Phys 2018; 146:124904. [PMID: 28388165 DOI: 10.1063/1.4978809] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An accurate time evolution of charged species having exponentially smeared out charge density (Slater type charge distribution) in dissipative particle dynamic (DPD) simulations necessitates the optimal choice of the Ewald splitting parameter (α), charge smearing length (λ), and real space cutoff (c) when the Ewald summation or its variant such as particle-particle particle-mesh or particle-mesh Ewald is employed for long range electrostatics. The present article offers the error estimates in the electrostatic energy and the force as a function of α and β(1/λ) on account of spherical truncation c in real space. These error estimate formulae are validated by our DPD simulation results. We also give here an Ewald-like derivation for electrostatic energy and force for the Slater type charge density. A quick estimate of the electrostatic pressure without the use of the tedious expression which involves three dimensional Fourier transforms is also presented, and its range of validity is discussed. The basis for the proposed formula for pressure is the fact that the minimum-image truncation in many cases allows one to compute the thermodynamic quantities with reasonable accuracy.
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Affiliation(s)
- Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076, India
| | - Sameer Jadhav
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076, India
| | - Rochish Thaokar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400 076, India
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36
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Lemarchand CA, Couty M, Rousseau B. Coarse-grained simulations of cis- and trans-polybutadiene: A bottom-up approach. J Chem Phys 2018; 146:074904. [PMID: 28228020 DOI: 10.1063/1.4975652] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We apply the dissipative particle dynamics strategy proposed by Hijón et al. [Faraday Discuss. 144, 301-322 (2010)] and based on an exact derivation of the generalized Langevin equation to cis- and trans-1,4-polybutadiene. We prove that it is able to reproduce not only the structural but also the dynamical properties of these polymers without any fitting parameter. A systematic study of the effect of the level of coarse-graining is done on cis-1,4-polybutadiene. We show that as the level of coarse-graining increases, the dynamical properties are better and better reproduced while the structural properties deviate more and more from those calculated in molecular dynamics (MD) simulations. We suggest two reasons for this behavior: the Markovian approximation is better satisfied as the level of coarse-graining increases, while the pair-wise approximation neglects important contributions due to the relative orientation of the beads at large levels of coarse-graining. Finally, we highlight a possible limit of the Markovian approximation: the fact that in constrained simulations, in which the centers-of-mass of the beads are kept constant, the bead rotational dynamics become extremely slow.
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Affiliation(s)
- Claire A Lemarchand
- Laboratoire de Chimie Physique, CNRS, Université Paris Sud, Bâtiment 349, 91405 Orsay Cedex, France
| | - Marc Couty
- Manufacture Française des Pneumatiques Michelin, Site de Ladoux, 23 Place des Carmes Déchaux, France Cedex 9, 63040 Clermont-Ferrand, France
| | - Bernard Rousseau
- Laboratoire de Chimie Physique, CNRS, Université Paris Sud, Bâtiment 349, 91405 Orsay Cedex, France
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37
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38
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Yoshimoto Y, Li Z, Kinefuchi I, Karniadakis GE. Construction of non-Markovian coarse-grained models employing the Mori–Zwanzig formalism and iterative Boltzmann inversion. J Chem Phys 2017; 147:244110. [DOI: 10.1063/1.5009041] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuta Yoshimoto
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Ikuya Kinefuchi
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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39
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Vaiwala R, Jadhav S, Thaokar R. Four-to-one coarse-grained polarisable water model for dissipative particle dynamics. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1405159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Sameer Jadhav
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Rochish Thaokar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
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40
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Ohkuma T, Kremer K. Comparison of two coarse-grained models of cis -polyisoprene with and without pressure correction. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.09.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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41
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Lu L, Li H, Bian X, Li X, Karniadakis GE. Mesoscopic Adaptive Resolution Scheme toward Understanding of Interactions between Sickle Cell Fibers. Biophys J 2017; 113:48-59. [PMID: 28700924 DOI: 10.1016/j.bpj.2017.05.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 12/17/2022] Open
Abstract
Understanding of intracellular polymerization of sickle hemoglobin (HbS) and subsequent interaction with the membrane of a red blood cell (RBC) is important to predict the altered morphologies and mechanical properties of sickle RBCs in sickle cell anemia. However, modeling the integrated processes of HbS nucleation, polymerization, HbS fiber interaction, and subsequent distortion of RBCs is challenging as they occur at multispatial scales, ranging from nanometers to micrometers. To make progress toward simulating the integrated processes, we propose a hybrid HbS fiber model, which couples fine-grained and coarse-grained HbS fiber models through a mesoscopic adaptive resolution scheme (MARS). To this end, we apply a microscopic model to capture the dynamic process of polymerization of HbS fibers, while maintaining the mechanical properties of polymerized HbS fibers by the mesoscopic model, thus providing a means of bridging the subcellular and cellular phenomena in sickle cell disease. At the subcellular level, this model can simulate HbS polymerization with preexisting HbS nuclei. At the cellular level, if combined with RBC models, the generated HbS fibers could be applied to study the morphologies and membrane stiffening of sickle RBCs. One important feature of the MARS is that it can be easily employed in other particle-based multiscale simulations where a dynamic coarse-graining and force-blending method is required. As demonstrations, we first apply the hybrid HbS fiber model to simulate the interactions of two growing fibers and find that their final configurations depend on the orientation and interaction distance between two fibers, in good agreement with experimental observations. We also model the formation of fiber bundles and domains so that we explore the mechanism that causes fiber branching.
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Affiliation(s)
- Lu Lu
- Division of Applied Mathematics, Brown University, Providence, Rhode Island
| | - He Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island
| | - Xin Bian
- Division of Applied Mathematics, Brown University, Providence, Rhode Island
| | - Xuejin Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island
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42
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Faure G, Delgado-Buscalioni R, Español P. The entropy of a complex molecule. J Chem Phys 2017; 146:224106. [PMID: 29166055 PMCID: PMC5468121 DOI: 10.1063/1.4984965] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 05/22/2017] [Indexed: 01/02/2023] Open
Abstract
Entropy is a central concept in the theory of coarse-graining. Through Einstein's formula, it provides the equilibrium probability distribution of the coarse-grained variables used to describe the system of interest. We study with molecular dynamics simulations the equilibrium probability distribution of thermal blobs representing at a coarse-grained level star polymer molecules in melt. Thermal blobs are characterized by the positions and momenta of the centers of mass, and internal energies of the molecules. We show that the entropy of the level of description of thermal blobs can be very well approximated as the sum of the thermodynamic entropy of each single molecule considered as isolated thermodynamic systems. The entropy of a single molecule depends on the intrinsic energy, involving only contributions from the atoms that make the molecule and not from the interactions with atoms of other molecules.
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Affiliation(s)
| | - Rafael Delgado-Buscalioni
- Departamento de Física Teórica de la Materia Condensada Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Pep Español
- Departamento de Física Fundamental, Universidad Nacional de Educación a Distancia, Apartado 60141, E-28080 Madrid, Spain
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Affiliation(s)
- Pep Español
- Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid, Spain
| | - Patrick B. Warren
- Unilever R&D Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, United Kingdom
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Izvekov S. Microscopic derivation of particle-based coarse-grained dynamics: Exact expression for memory function. J Chem Phys 2017; 146:124109. [DOI: 10.1063/1.4978572] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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45
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Li Z, Bian X, Yang X, Karniadakis GE. A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization. J Chem Phys 2017; 145:044102. [PMID: 27475343 DOI: 10.1063/1.4959121] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We construct effective coarse-grained (CG) models for polymeric fluids by employing two coarse-graining strategies. The first one is a forward-coarse-graining procedure by the Mori-Zwanzig (MZ) projection while the other one applies a reverse-coarse-graining procedure, such as the iterative Boltzmann inversion (IBI) and the stochastic parametric optimization (SPO). More specifically, we perform molecular dynamics (MD) simulations of star polymer melts to provide the atomistic fields to be coarse-grained. Each molecule of a star polymer with internal degrees of freedom is coarsened into a single CG particle and the effective interactions between CG particles can be either evaluated directly from microscopic dynamics based on the MZ formalism, or obtained by the reverse methods, i.e., IBI and SPO. The forward procedure has no free parameters to tune and recovers the MD system faithfully. For the reverse procedure, we find that the parameters in CG models cannot be selected arbitrarily. If the free parameters are properly defined, the reverse CG procedure also yields an accurate effective potential. Moreover, we explain how an aggressive coarse-graining procedure introduces the many-body effect, which makes the pairwise potential invalid for the same system at densities away from the training point. From this work, general guidelines for coarse-graining of polymeric fluids can be drawn.
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Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xin Bian
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Xiu Yang
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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46
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Li Z, Lee HS, Darve E, Karniadakis GE. Computing the non-Markovian coarse-grained interactions derived from the Mori–Zwanzig formalism in molecular systems: Application to polymer melts. J Chem Phys 2017; 146:014104. [DOI: 10.1063/1.4973347] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Hee Sun Lee
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA
| | - Eric Darve
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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47
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Davtyan A, Voth GA, Andersen HC. Dynamic force matching: Construction of dynamic coarse-grained models with realistic short time dynamics and accurate long time dynamics. J Chem Phys 2016; 145:224107. [DOI: 10.1063/1.4971430] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Aram Davtyan
- Department of Chemistry, The James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory A. Voth
- Department of Chemistry, The James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Hans C. Andersen
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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48
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Ma L, Li X, Liu C. The derivation and approximation of coarse-grained dynamics from Langevin dynamics. J Chem Phys 2016; 145:204117. [DOI: 10.1063/1.4967936] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Lina Ma
- Department of Mathematics, The Pennsylvania State University, University Park, Pennsylvania 16802-6400, USA
| | - Xiantao Li
- Department of Mathematics, The Pennsylvania State University, University Park, Pennsylvania 16802-6400, USA
| | - Chun Liu
- Department of Mathematics, The Pennsylvania State University, University Park, Pennsylvania 16802-6400, USA
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49
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Deng M, Li Z, Borodin O, Karniadakis GE. cDPD: A new dissipative particle dynamics method for modeling electrokinetic phenomena at the mesoscale. J Chem Phys 2016; 145:144109. [DOI: 10.1063/1.4964628] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Mingge Deng
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Zhen Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Oleg Borodin
- Electrochemistry Branch, Sensors and Electron Devices Directorate, U.S. Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
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50
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Abstract
We consider the Brownian motion of a particle and present a tutorial review over the last 111 years since Einstein's paper in 1905. We describe Einstein's model, Langevin's model and the hydrodynamic models, with increasing sophistication on the hydrodynamic interactions between the particle and the fluid. In recent years, the effects of interfaces on the nearby Brownian motion have been the focus of several investigations. We summarize various results and discuss some of the controversies associated with new findings about the changes in Brownian motion induced by the interface.
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Affiliation(s)
- Xin Bian
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
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