Using C-DFT to develop an e-ReaxFF force field for acetophenone radical anion

Autor:	Maximiliano Aldo Burgess, Adri C. T. van Duin, Katheryn A. Penrod, Ismaila Dabo, Dooman Akbarian, Woodward William H H
Rok vydání:	2021
Předmět:	Molecular dynamics chemistry.chemical_compound chemistry Force field (physics) Chemical physics Electron affinity Atom General Physics and Astronomy Power cable Density functional theory Physical and Theoretical Chemistry ReaxFF Acetophenone
Zdroj:	The Journal of Chemical Physics. 155:214104
ISSN:	1089-7690 0021-9606
DOI:	10.1063/5.0064705
Popis:	Increased electricity usage over the past several decades has accelerated the need for efficient high-voltage power transmission with reliable insulating materials. Cross-linked polyethylene (XLPE) prepared via dicumyl peroxide (DCP) cross-linking has emerged as the insulator of choice for modern power cables. Although DCP cross-linking generates the desired XLPE product in high yield, other by-products are also produced. One such by-product, acetophenone, is particularly intriguing due to its aromaticity and positive electron affinity. In this work, constrained density functional theory (C-DFT) was utilized to develop an e-ReaxFF force field suitable for describing the acetophenone radical anion. Initial parameters were taken from the 2021 Akbarian e-ReaxFF force field, which was developed to describe XLPE chemistry. Then, C-DFT geometry optimizations were performed wherein an excess electron was constrained to each atom of acetophenone. The resulting C-DFT energy values for the various electronic positions were added to the e-ReaxFF training set. Next, an analogous set of structures was energy-minimized using e-ReaxFF, and equilibrium mixture compositions for the two methods were compared at multiple temperatures. Iterative fitting against C-DFT energy data was performed until satisfactory agreement was achieved. To test force field performance, molecular dynamics simulations were performed in e-ReaxFF and the resulting electronic distributions were qualitatively compared to unconstrained-DFT spin density data. By expanding our e-ReaxFF force field for XLPE, namely, adding the capability to describe acetophenone and its interactions with an excess electron, we move one step closer to a comprehensive molecular understanding of XLPE chemistry in a high-voltage power cable.
Databáze:	OpenAIRE
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