Valence energy correction for electron reactive force field

Abstract

Reactive force fields (ReaxFF) are a classical method to describe material properties based on a bond‐order formalism, that allows bond dissociation and consequently investigations of reactive systems. Semiclassical treatment of electrons was introduced within ReaxFF simulations, better known as electron reactive force fields (eReaxFF), to explicitly treat electrons as spherical Gaussian waves. In the original version of eReaxFF, the electrons and electron–holes can lead to changes in both the bond energy and the Coulomb energy of the system. In the present study, the method was modified to allow an electron to modify the valence energy, therefore, permitting that the electron's presence modifies the three‐body interactions, affecting the angle among three atoms. When a reaction path involving electron transfer is more sensitive to the geometric configuration of the molecules, corrections in the angular structure in the presence of electrons become more relevant; in this case, bond dissociation may not be enough to describe a reaction path. Consequently, the application of the extended eReaxFF method developed in this work should provide an improved description of a reaction path. As a first demonstration this semiclassical force field was parametrized for hydrogen and oxygen interactions, including water and water's ions. With the modified methodology both the overall accuracy of the force field but also the description of the angles within the molecules in presence of electrons could be improved.

Molecular Dynamics Simulations of Soft and Reactive Landing of Proteins Desorbed by Argon Cluster Bombardment

“…Investigating RL simulations, a delineation of the structural characteristics of deposited films unfolds, elucidating the polymerization of deposited molecules and the generation of amorphous carbon materials during the landing process. − Less computer intensive than QM methods (DFT), classical molecular dynamics (MD) using chemical reactive force fields (Brenner, COMB, AIREBO, ReaxFF) appears to be the method of choice to study soft and reactive landing (and the transition between the two) for large systems, long times, or repeated impact simulations. In particular, the implementation of ReaxFF − has emerged as a fitting methodology for investigating protein SL and RL, having been effectively employed in studying various phenomena, such as the fragmentation of polymer surfaces during cluster collisions or the sputtering of amino acids by GCIB from bulk solids and from graphite substrates. , Additionally, recent enhancements in the ReaxFF code display promising advancements by enabling explicit simulation of electrons and accelerating the computation of charges. − …”

Unraveling the Molecular Dynamics of Glucose Oxidase Desorption Induced by Argon Cluster Collision

“…Remarkably, the reactive force field (ReaxFF) can perform bond-order calculation and reactions on the fly, − which includes the fragmentation processes occurring during the sputtering of biomolecules by argon GCIB. Since recently, algorithms implemented in the ReaxFF can simulate the behavior of electrons and electrons–holes as semiclassical particles, − opening up perspectives to study ion formation induced by a collision with Ar clusters. Notably, ReaxFF simulations have demonstrated a relationship between fragmentation upon impact and distribution of bond types.…”