Intrinsic Bond Energies: A Real Space Point of View
A. Martín Pendás
Dpto. Química Física y Analítica, Universidad de Oviedo, Oviedo, Espagne.
Lundi 12 Septembre 2016, 12h00
bibliothèque LCT, tour 12 - 13, 4e étage
A not completely extinguished fire on the nature of the chemical bond in the C2 molecule [1] has re-openened several dormant fronts on the interpretation of bond energies. One of these regards whether we should measure bond strengths with respect to the ground states of the isolated fragments that become bonded, leading to standard bond dissociation energies (BDE), or if appropriately "prepared for bonding, i.e. excited, states should be used instead. The latter view provides larger bond energies, which are usually called intrinsic bond energies (IBE) [2]. Here we examine this problem from a real space partitioning point of view, using the Interacting Quantum Atoms (IQA) approach [3] and electron number distribution functions (EDF) [4]. In IQA, the molecular energy is exactly written as a sum of atomic or fragment self-energies and interatomic (or inter-fragment) interaction energies. The evolution of self-energies along bonding coordinates allows for the identification of the proper atomic/fragment state that reflects the actual electronic state of each fragment in-the-molecule, which can then be used to properly define IBEs. Some results on methane, ethene, ethyne and dinitrogen will be shown.
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[3] M. A. Blanco, A. Martín Pendás, E. Francisco J. Chem. Theory Comput. 1, 1096 (2005).
[4] E. Francisco, A. Martín Pendás, M. A. Blanco J. Chem. Phys. 126, 094102 (2007).