Parameterizing Complex Reactive Force Fields Using Multiple Objective Evolutionary Strategies (MOES): Part 2: Transferability of ReaxFF Models to C–H–N–O Energetic Materials

Abstract

The Multiple Objective Evolutionary Strategies (MOES) algorithm was used to parametrize force fields having the form of the reactive models ReaxFF (van Duin, A. C. T.; Dasgupta, S.; Lorant, F.; Goddard, W. A. J. Phys. Chem. A 2001, 105, 9396) and ReaxFF-lg (Liu, L.; Liu, Y.; Zybin, S. V.; Sun, H.; Goddard, W. A. J. Phys. Chem. A 2011, 115, 11016) in an attempt to produce equal or superior ambient state crystallographic structural results for cyclotrimethylene trinitramine (RDX). Promising candidates were then subjected to molecular dynamics simulations of five other well-known conventional energetic materials to assess the degree of transferability of the models. Two models generated through the MOES search were shown to have performance better than or as good as ReaxFF-lg in describing the six energetic systems modeled. This study shows that MOES is an effective and efficient method to develop complex force fields.

The ReaxFF reactive force-field: development, applications and future directions

“…In particular, MC and genetic algorithm (GA) based approaches have risen in popularity. [145][146][147][148][149] So far, these methods have only been used for isolated force-field development efforts, and as such they still have to demonstrate their transferability and user friendliness. They do hold promise for reducing force-field development time, as well as for making the process more accessible to nonexpert users.…”

A Comparative Density Functional Theory and Density Functional Tight Binding Study of Phases of Nitrogen Including a High Energy Density Material N8

“…Also desired are low cost of inputs and of synthesis as well as low environmental impact of both inputs and the products of decomposition. New HEDMs are actively researched experimentally as well as computationally [2][3][4][5][6][7][8][9]. Most effective molecular HEDM contain nitrogen-and oxygen-containing heterocycles and/or NOx moieties [10].…”

“…Most effective molecular HEDM contain nitrogen-and oxygen-containing heterocycles and/or NOx moieties [10]. The decomposition of such molecules usually leads to the release of COx, NOx and cyanogen molecules which are toxic or environmentally damaging [2][3][4][5][6][7][8][9].…”

Efficient global optimization of reactive force‐field parameters

“…Shortly before the present article was submitted, a pair of papers by Weingarten et al was published. These authors reoptimized 46 parameters of a previously published ReaxFF parametrization for two explosives, using mutation‐only evolutionary strategies in a multi‐objective setting.…”

“… are single‐objective GA optimization techniques. Recently, a number of studies using multi‐objective GA techniques to optimize ReaxFF parameters were published (see Section Related Work). In a single‐objective scheme, it is necessary to predetermine the weights for individual entities in the fitness function.…”