Titre :

vdW-TSSCDS: An automated procedure for the computation of stationary points on intermolecular potential energy surfaces

Auteur(s) :

Kopec, Sabine [Orateur]
Physico-Chimie Moléculaire Théorique [PCMT]
Martinez-Nunez, Emilio [Auteur]
Soto, Juan Martin [Auteur]
Peláez, Daniel [Auteur]
Physico-Chimie Moléculaire Théorique [PCMT]

Titre de la manifestation scientifique :

High Dimensional Quantum Dynamics (HDQD)

Ville :

Lille

Pays :

France

Date de début de la manifestation scientifique :

2018-08-28

Date de publication :

2018-08-28

Discipline(s) HAL :

Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]

Résumé en anglais : [en]

Characterisation of the topography of Potential Energy Surfaces (PESs) is a tedious task and for large dimensional systems not an evident one. Recently, an automatic methodology (TSSCDS) for the automatic determination of ...
Lire la suite >Characterisation of the topography of Potential Energy Surfaces (PESs) is a tedious task and for large dimensional systems not an evident one. Recently, an automatic methodology (TSSCDS) for the automatic determination of the stationary points on a PES was proposed by one of the authors [1]. Given a chemically bound molecular system, this methodology relies on a comprehensive sampling of the PES using direct dynamics (semiempirical) simulations and a graph-theory based algorithm to provide transition state guess structures, which are subsequently optimized at an appropriate higher level of theory. A relevant concept in this algorithm is the definition of an adjacency matrix, a square symmetric matrix of dimension of the number of atoms, whose elements indicate whether the corresponding atoms are bound or not. This character, in turn, depends on the definition of a set of covalent radii values.We have generalized the TSSCDS methodology to study van der Waals and more generally non-covalently bound complexes (vdW-TSSCDS) [2]. Considering such a complex as composed by two well-identifiable fragments, the key idea is the redefinition of the adjacency matrix in a block structure. In this picture, diagonal blocks correspond to the isolated fragments and off-diagonal blocks provide the intermolecular connectivity. To this end, we introduce a new definition of bound or not in a van der Waals sense, by utilizing an extra set of van der Waals distances to determine the elements in the off-diagonal blocks. Additionally, instead of the widely employed rigid approach to the study of intermolecular PES, we have relaxed this condition by adopting a semi-rigid approach in which one of the fragments remains fixed at its equilibrium geometry whereas the other is fully flexible. This gives us the opportunity to study the influence of a substrate on the spectroscopy and reactivity of an adsorbed molecule.We here present the application to test systems, showing that vdW-TSSCDS does lead to the correct ab initio topography even in limiting cases such as extremely flat regions of the surfaces or non-trivial topologies such as in the case of bifurcation points.References:[1] a) E. Martínez-Núñez, J. Comp. Chem. 36, 222 (2015).b) E. Martínez-Núñez, Phys. Chem. Chem. Phys. 17, 14912 (2015).[2] S. Kopec, E. Martínez-Núñez, J. Soto, D. Peláez, submitted (2018).Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Collections :

• Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM) - UMR 8523

Source :

Harvested from HAL