scholarly journals Multipolar Force Fields for Atomistic Simulations

2020 ◽  
Author(s):  
Rebecca Lindsey ◽  
Laurence E. Fried ◽  
Nir Goldman ◽  
Sorin Bastea

Machine learned reactive force fields based on polynomial expansions have been shown to be highly effective for describing simulations involving reactive materials. Nevertheless, the highly flexible nature of these models can give rise to a large number of candidate parameters for complicated systems. In these cases, reliable parameterization requires a well-formed training set, which can be difficult to achieve through standard iterative fitting methods. Here we present an active learning approach based on cluster analysis and Shannon information theory to enable semi-automated generation of informative training sets and robust machine learned force fields. Use of this tool is demonstrated for development of a model based on linear combinations of Chebyshev polynomials explicitly describing up to four-body interactions, for a chemically and structurally diverse system of C/O under extreme conditions. We show that this flexible training repository management approach enables development of models exhibiting excellent agreement with Kohn–Sham density functional theory (DFT) in terms of structure, dynamics, and speciation.


2007 ◽  
Vol 111 (9) ◽  
pp. 2130-2137 ◽  
Author(s):  
Ivo Cacelli ◽  
Luca De Gaetani ◽  
Giacomo Prampolini ◽  
Alessandro Tani

2020 ◽  
Author(s):  
Rebecca Lindsey ◽  
Laurence E. Fried ◽  
Nir Goldman ◽  
Sorin Bastea

Machine learned reactive force fields based on polynomial expansions have been shown to be highly effective for describing simulations involving reactive materials. Nevertheless, the highly flexible nature of these models can give rise to a large number of candidate parameters for complicated systems. In these cases, reliable parameterization requires a well-formed training set, which can be difficult to achieve through standard iterative fitting methods. Here we present an active learning approach based on cluster analysis and Shannon information theory to enable semi-automated generation of informative training sets and robust machine learned force fields. Use of this tool is demonstrated for development of a model based on linear combinations of Chebyshev polynomials explicitly describing up to four-body interactions, for a chemically and structurally diverse system of C/O under extreme conditions. We show that this flexible training repository management approach enables development of models exhibiting excellent agreement with Kohn–Sham density functional theory (DFT) in terms of structure, dynamics, and speciation.


2018 ◽  
Vol 45 (4-5) ◽  
pp. 310-321 ◽  
Author(s):  
Shalini J. Rukmani ◽  
Grit Kupgan ◽  
Dylan M. Anstine ◽  
Coray M. Colina

2013 ◽  
Vol 35 (1) ◽  
pp. 18-29 ◽  
Author(s):  
Franziska D. Hofmann ◽  
Michael Devereux ◽  
Andreas Pfaltz ◽  
Markus Meuwly

Author(s):  
John W. Coleman

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.


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