Journal of Computational Chemistry · 2019 · 10 citations · 22 references
A dissociative force field for all-atomistic molecular dynamics calculations has been developed to investigate impact fracture of polymers accompanying dissociation of chemical bonds of polymer main chain. Energy of dimer molecules was evaluated as a function of both bond-length b and bond-angle θ by CASPT2 calculations, whose quality is enough to describe dissociation of chemical bonds. Because we found that the bond dissociation energy D decreases with increasing bond-angle, we employed the Morse-type function V<sub>Bond</sub> (b, θ) = {D - V<sub>Angle</sub> (θ)}[1 - exp{-α(b - b<sub>0</sub> ) - β(b - b<sub>0</sub> )<sup>2</sup> }] where a quartic function V<sub>Angle</sub> (θ) = k<sub>1</sub> (θ - θ<sub>0</sub> ) + k<sub>2</sub> (θ - θ<sub>0</sub> )<sup>2</sup> + k<sub>3</sub> (θ - θ<sub>0</sub> )<sup>3</sup> + k<sub>4</sub> (θ - θ<sub>0</sub> )<sup>4</sup> . This function reproduced well the CASPT2 potential energy surface in a wide range of b and θ. The parameters have been obtained for four popular glassy polymers, polyethylene, poly(methyl methacrylate), poly(styrene), and polycarbonate. © 2019 Wiley Periodicals, Inc.
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William L. Jorgensen, David S. Maxwell, Julian Tirado‐Rives · Journal of the American Chemical Society · 1996 · 15K citations
Organic Molecules, Engineering, Conformational Energetics +13