Search

The generation of reference data for deep learning models is challenging for reactive systems, and more so for combustion reactions due to the extreme conditions that create radical species and alternative spin states during the combustion process. Here, we extend intrinsic reaction coordinate (IRC) calculations with ab initio MD simulations and normal mode displacement calculations to more extensively cover the potential energy surface for 19 reaction channels for hydrogen combustion. A total of ∼290,000 potential energies and ∼1,270,000 nuclear force vectors are evaluated with a high quality range-separated hybrid density functional, ωB97X-V, to construct the reference data set, including transition state ensembles, for the deep learning models to study hydrogen combustion reaction. Measurement(s) ab initio energies and forces of hydrogen combustion Technology Type(s) density functional theory • ab initio molecular dynamics • normal modes Factor Type(s) cartesian coordinates [ABSTRACT FROM AUTHOR]

We provide a general (yet elementary) proof of Pearson's hard/soft acid/base principle. Contrary to previous attempts to justify this rule, we go beyond the venerable parabolic model of Parr and Pearson. This new treatment encompasses more realistic E versus N dependencies, while emphasizing the importance of the correct normalization of these models. [ABSTRACT FROM AUTHOR]

We show that the statistical divergence measures associated with non-extensive thermodynamic entropy functions-specifically the Tsallis, Réyni, Sharma-Mittal, supraextensive, and H-divergences-are associated with the Hirshfeld atoms-in-molecules partitioning. This extends the treatment of Nalewajski and Parr (J Phys Chem A 109:3957-3959, 2005), (for the extensive Shannon entropy) to non-extensive entropy measures. It also extends the work of Heidar-Zadeh and Ayers (J Chem Phys 142(4):044107, 2015), (for divergence measures that are local density functionals) to non-local functionals. These results dramatically extend the mathematical framework that one can use for similarity-based atoms-in-molecules partitioning. [ABSTRACT FROM AUTHOR]

We consider the problem of defining an appropriate local descriptor corresponding to an arbitrary global descriptor. Although it does not seem easy to rigorously and uniquely define local analogues of derived global descriptors (e.g., the electrophilicity) or the fundamental global descriptors associated with the canonical ensemble (e.g., the hardness), the local response of these global descriptors can be defined unambiguously. We look at the local response of the global electrophilicity and compare it to the conventional, ad hoc, definition of the local electrophilicity. The local response of global nucleofugality and electrofugality is also discussed. [ABSTRACT FROM AUTHOR]