2023-12-20 23:00:00
The industry is increasingly synthesizing new molecules and new materials with the aim of discovering new properties. Due to the constant increase in the quality of manufactured products and the precision required for their development, a new need has emerged: that of controlling chemical reactions at the atomic level. The thermodynamics of chemical reactions is entirely governed by the difference in free enthalpy, denoted ΔG, between an initial stable state composed of reactants and a final stable state composed of products. The kinetics of the reaction is, for its part, determined by the enthalpy barrier, noted G bwhich must be crossed to move from the initial state to the final state, crossing an unstable state known astransition state or saddle point. Thus, knowledge of these energies throughout the chemical reaction is of crucial importance for mastering modern chemistry and applications in materials science. However, this represents a major algorithmic challenge, because the potential energy E of the physical system depends on the positions (x, y, z) of all N at atoms that compose it. Potential energy is therefore a function of 3N at dimensions which is generally extremely expensive to calculate for a given set of atomic positions.
The most accurate methodology for modeling the energy of an atomic system is to use calculations from the beginning, which take into account the electronic structure of atoms by solving the Hamiltonian of the system. However, determining the energy of an atomic system and exploring this potential energy surface with such precision represents a high computational cost. It is therefore essential to have an algorithm capable of efficiently exploring the potential energy surface from an initial state while minimizing the number of calculations required.
The objective of this article is to present the activation-relaxation technique (named “ARTn” for activation-relaxation technique new), an extremely effective method for blindly discovering the different stable and metastable states on an energy surface. high-dimensional potential, whatever the energy model used, and to precisely characterize the transition point of molecular reactions. ARTn has already been applied with great success to a wide range of complex systems and can in principle be used for any system, from protein aggregation to surface reactions or even diffusion in glassy materials. In the rest of this article, we will calculate the potential energy surfaces at 0 K and the entropic effects will be neglected: E = G.
Key points
Domaine : materials engineering, predictive modeling
Degree of diffusion of technology : maturity
Technologies involved : software for modeling and simulation of the electronic structure of materials
Application areas : materials sciences and modern chemistry
Main French players : LAST-CNRS
– Competitiveness clusters : chemical industry, theoretical physics, metallurgy, microelectronics industry
– Competence centers : engineering and nanostructuring of materials
Other actors around the world : University of Montreal, CNR-IOM, CEA
Contact : [email protected], [email protected], [email protected]
1703349669
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