Automatic and Systematic Atomistic Simulations in the MedeA® Software Environment: Application to EU-REACH

This work demonstrates the systematic prediction of thermodynamic properties for batches of thousands of molecules using automated procedures. This is accomplished with newly developed tools and functions within the Material Exploration and Design Analysis (MedeA®) software environment, which handle the automatic execution of sequences of tasks for large numbers of molecules including the creation of 3D molecular models from 1D representations, systematic exploration of possible conformers for each molecule, the creation and submission of computational tasks for property calculations on parallel computers, and the post-processing for comparison with available experimental properties. After the description of the different MedeA® functionalities and methods that make it easy to perform such large number of computations, we illustrate the strength and power of the approach with selected examples from molecular mechanics and quantum chemical simulations. Specifically, comparisons of thermochemical data with quantum-based heat capacities and standard energies of formation have been obtained for more than 2 000 compounds, yielding average deviations with experiments of less than 4% with the Design Institute for Physical PRoperties (DIPPR) database. The automatic calculation of the density of molecular fluids is demonstrated for 192 systems. The relaxation to minimum-energy structures and the calculation of vibrational frequencies of 5 869 molecules are evaluated automatically using a semi-empirical quantum mechanical approach with a success rate of 99.9%. The present approach is scalable to large number of molecules, thus opening exciting possibilities with the advent of exascale computing. Ce travail démontre notre capacité à prédire systématiquement les propriétés thermodynamiques par lot de plusieurs milliers de molécules en utilisant des procédures automatique. Ceci est accompli à l’aide de nouveaux outils et fonctions intégrés dans l’environnement logiciel de MedeA® (Material Exploration and Design Analysis), qui manipule l’exécution automatique de séquences de tâches sur de grands nombres de molécules comprenant la création de modèles moléculaires 3D à partir de représentations 1D, l’exploration systématique des conformations possibles pour chaque molécules, la création et la soumission de tâches informatiques pour calculer des propriétés sur des ordinateurs parallèles, et le post-traitement par comparaison avec les propriétés experimentales disponibles.