Reaction rates in a theory of mechanochemical pathways

Int J of Quantum Chemistry

Bofill

Ribas‐Ariño

2018

Self Cite

A core idea in the context of mechanochemistry is that applying an external tensile force along a reaction coordinate should enhance the chemical reaction of interest. Here, we analyze perturbed generic molecular structures: schematic models of triatomics, ABC, and tetraatomics, AABB. They are used to demonstrate that pulling does usually not use the “reaction coordinate,” but opens new reaction pathways. Within development of these models we use the concept of Newton trajectories for a theory of mechanochemistry. However, we find cases where the theory of Newton trajectories is not applicable. For all cases, we define the curve of force‐displaced stationary points, and we discuss the importance of barrier breakdown points and valley‐ridge inflection points. The examples use Morse potentials for bonds and simple angle functions and are demonstrated by assumed real values for the potential parameters. On the basis of the systematic study of some generic models we explain a set of already observed experimental mechanochemical phenomena in specific molecular systems and we apply the results to the strength of chemical bonds.

Section: Discussionmentioning

confidence: 99%

“…In between there has to be a maximum of ∣ g ∣, compare Equation . Here, holds the condition

italicDet ((), boldH ((), x)) = 0

with the Hessian of the original PES, V ( x ).…”

Section: Application Of Newton Trajectoriesmentioning

confidence: 99%

“…

italicDet ((), boldH ((), x)) = 0

Section: Application Of Newton Trajectoriesmentioning

confidence: 99%

Section: Application Of Newton Trajectoriesmentioning

confidence: 99%

g_{W} = W {(D_{1} β_{1}, D_{2} β_{2})}^{T}

with eigenvalue zero and its orthogonal eigenvector with zero eigenvalue is

g_{W}^{⊥} = W {(D_{2} β_{2}, - D_{1} β_{1})}^{T}

, where W is the normalization factor,

W = {(D_{1}^{2} β_{1}^{2} + D_{2}^{2} β_{2}^{2})}^{- 1 / 2}

.…”

Section: Model Pes For Pulling a Linear Abc Moleculementioning

confidence: 99%

See 3 more Smart Citations

Toward a theory of mechanochemistry: Simple models from the very beginnings

Int J of Quantum Chemistry

Bofill

Ribas‐Ariño

2018

Self Cite

Some Mathematical Reasoning on the Artificial Force Induced Reaction Method

Bofill

2019

J Comput Chem

There are works of the Maeda–Morokuma group, which propose the artificial force induced reaction (AFIR) method (Maeda et al., J. Comput. Chem. 2014, 35, 166 and 2018, 39, 233). We study this important method from a theoretical point of view. The understanding of the proposers does not use the barrier breakdown point of the AFIR parameter, which usually is half of the reaction path between the minimum and the transition state which is searched for. Based on a comparison with the theory of Newton trajectories, we could better understand the method. It allows us to follow along some reaction pathways from minimum to saddle point, or vice versa. We discuss some well‐known two‐dimensional test surfaces where we calculate full AFIR pathways. If one has special AFIR curves at hand, one can also study the behavior of the ansatz. © 2019 The Authors. Journal of Computational Chemistry published by Wiley Periodicals, Inc.

Mechanochemistry on the Müller–Brown surface by Newton trajectories

Int J of Quantum Chemistry

Bofill²

2017

Self Cite

Chemical processes which suffer the application of mechanical force are theoretically described by effective potential energy surfaces (PES). We worked out [Theor. Chem. Acc. 135, 113 (2016)] that the changes due to the force for the minimums and for the saddle points can be described by Newton trajectories (NT) of the original PES. If the force is so high that the saddle point disappears into a shoulder then the mechanochemical action is fulfilled: the pulling force breaks down the reaction barrier. The point is named barrier breakdown point (BBP). Different families of NTs form corridors on the original PES which describe qualitative different actions of the force. The border regions of such corridors are governed by the valley-ridge inflection points (VRI) of the surface. Here we discuss all this on the basis of the well known Müller-Brown (MB) surface, and we describe a new kind of NT-corridor.