Characterisation of halogen bonds by means of an underexplored scalar function: the DFT electronic correlation potential.

MATIAS O. MIRANDA; VICTOR M. RAYÓN; DARÍO J. R. DUARTE

Valladolid

Jornada; 1° Jornada de Estudiantes del Programa de Estudiantes de Doctorado en Química; 2023

Universidad de Valladolid

Electronic correlation is a quantum phenomenon that can be understood through Fermicorrelation, arising from the symmetry requirements of the exact wave function, and the Coulombcorrelation, arising from the mutual Coulomb repulsion between the electrons.[1] The correlationpotential (Vc) can be extracted from the Kohn-Sham exchange-correlation potential (Vxc), which isdefined through a characteristic exchange-correlation energy functional Exc applied in DFT.[2] In thiswork, the underexplored topology of Vc has been studied on the conventional halogen bonds YX···FH,with Y = F, Cl, Br, I and X = Cl, Br, I. The Vc scalar field has been obtained from thePerdew-Burke-Ernzerhof (PBE) DFT functional, with the Multiwfn program.[3]The radial variation of Vc with respect to the nuclei shows a well-defined layered structure,where the number of minima coincides with the number of occupied electron layers. On the otherhand, halogen bonds exhibit a region of Vc depression in the interatomic region, whose depth andasymmetry increase with the polarity of the interaction. Although these correlations have not beenexhaustively studied, they suggest that Vc could be a useful tool for characterizing interactions, as wellas for a general study of the electronic structure of atoms in molecules.References[1] Tew DP, Klopper W, Helgaker T. Electron correlation: the many-body problem at the heart of chemistry. J. Comput Chem. 2007 Jun; 28 (8): 1307-1320.[2] Rogelio Cuevas-Saavedra, Paul W. Ayers, Viktor N. Staroverov; Kohn–Sham exchange-correlation potentialsfrom second-order reduced density matrices. J. Chem. Phys. 28 December 2015; 143 (24): 244116.[3] Lu, Tian & Chen, Feiwu. (2012). Multiwfn: A multifunctional wavefunction analyzer. Journal of computationalchemistry. 33. 580-9.