Development of a Charge-Implicit ReaxFF for C/H/O Systems

Abstract

Modeling chemical reactions in condensed phases is difficult. Interaction potentials (or force fields) like ReaxFF can perform this modeling with a high overall accuracy, but the disadvantage of ReaxFF is a low simulation speed arising from costly algorithms, in particular charge equilibration. Therefore, we reparametrized ReaxFF to incorporate Coulomb forces into other terms of the force field. Because of this change, our charge-implicit ReaxFF-CHO is >2 times faster than the original parametrization. Despite the lack of explicit electrostatic interactions, our potential can correctly model the reactions and densities of systems containing carbon, hydrogen, and oxygen atoms. We have used the new potential to simulate bombardment of trehalose by water clusters. It has been observed experimentally that these water projectiles can increase the sensitivity of secondary ion mass spectrometry by more than an order of magnitude, but no explanation for this phenomenon was given. Our simulations show that the increase in the intensity of the recorded signal coincides with the emission of trehalose–water complexes.

Alternative Local Melting‐Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

“…The reason for observing such a difference is attributed to the basic tendency of Cu 0 / Cu 2+ to be oxidized/reduced in ethanol, depending on the oxygen content of the box, which is also confirmed by DFT calculations (Part S1f, Supporting Information). [ 71–76 ]…”

“…The reason for observing such a difference is attributed to the basic tendency of Cu 0 /Cu 2+ to be oxidized/reduced in ethanol, depending on the oxygen content of the box, which is also confirmed by DFT calculations (Part S1f, Supporting Information). [71][72][73][74][75][76] According to the results of DFT, the calculated absorption energies of ethanol on the surfaces of Cu (111) and CuO (111) indicate that metallic copper, due to its higher oxidation tendency, is more willing to absorb ethanol by combining with both oxygen and hydrogen of the OH group. CuO, on the other hand, absorbs only the H atom of the OH group with a comparatively smaller tendency.…”

“…𝑂 2 = 𝐶𝑢 2 𝑂), while ethanol absorbs oxygen from copper oxide (𝐶 2 𝐻 5 𝑂𝐻 + 2𝑂 2 = 2𝐶𝑂 2 + 3𝐻 2 𝑂), both for oxidation purposes [26][27][28][29][30][31]. By changing the temperature of the simulation box (models MB3 and MB4), the only difference detected was the ethanol decomposition rate, which was found to be 0.60, 5.35, and 55.42 molecules/ps for the solvents decomposed at 1000, 1500, and 2843 ̊ K, respectively.…”

Probing Atomic-Scale Processes at the Ferrihydrite-Water Interface With Reactive Molecular Dynamics

“…In contrast to classical MD, where hydrogen bonds are not predefined and are instead determined based on energy and geometric criteria 81 , the ReaxFF force field declares hydrogen bonding a priori in our reactive simulations. This approach enables more realistic simulations, particularly effective in predicting the short-range cohesive forces within water 82 .…”

Probing atomic-scale processes at the ferrihydrite-water interface with reactive molecular dynamics

“…In contrast to classical MD, where hydrogen bonds are not predefined and are instead determined based on energy and geometric criteria [56], the ReaxFF force field declares hydrogen bonding a priori in our reactive simulations. This approach enables more realistic simulations, particularly effective in predicting the short-range cohesive forces within water [57].…”