XXXVI Reunión Bienal de la Real Sociedad Española de Física

Intrinsic Bond Energies: A real space point of view

18 jul. 2017 18:00

20m

Aula Matemáticas (Facultad de Química (USC))

Oral parallel contribution Molecular Physics at the Edge Molecular Physics at the Edge I

Descripción

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, dinitrogen, and dicarbon will be shown. Acknowledgments We thank the spanish MINECO, grant CTQ2015-65790-P, the FICyT, grant GRUPIN14-049, and the European Union FEDER funds for financial support. References [1] S. Shaik, H. S. Rzepa, R. Hoffmann, Angew. Chemie Intl. Ed , 52. (2013) 3020. [2] D. Cremer, A. Wu, A. Larsson, E. Kraka, J. Mol. Model. 6. (2000) 296 [3] M. A. Blanco, A. Martín Pendás, E. Francisco, J. Chem. Theory Comput. 1 (2005) 1096. [4] E. Francisco, A. Martín Pendás, M. A. Blanco, J. Chem. Phys. 126 (2007) 094102