title: Testing the tools for revealing and characterizing the iodine-iodine halogen bond in crystals.
abstract: To understand what tools are really suitable to identify and classify the iodine-iodine non-covalent interactions in solid organic polyiodides, we have examined the anisotropy of the electron density within the iodine atomic basin along and across the iodine-iodine halogen bond using the Laplacian of electron density, one-electron potential and electron localization function produced by Kohn-Sham calculations with periodic boundary conditions. The Laplacian of electron density exhibits the smallest anisotropy and yields a vague picture of the outermost electronic shells. The one-electron potential does not show such a deficiency and reveals that the valence electron shell for the halogen-bond acceptor iodine is always wider than that for the halogen-bond donor iodine along its σ-hole direction. We have concluded that the one-electron potential is the most suitable for classification of the iodine-iodine bonds and interactions in complicated cases, while the electron localization function allows to distinguish the diiodine molecule bonded with the monoiodide anion from the typical triiodide anion.
authors.affiliation: Chemistry Department, South Ural State University, 76 Lenin ave, Chelyabinsk 454080, Russian Federation.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Bartashevich
authors.affiliation: Chemistry Department, South Ural State University, 76 Lenin ave, Chelyabinsk 454080, Russian Federation.
authors.forename: Irina
authors.initials: I
authors.lastname: Yushina
authors.affiliation: Chemistry Department, South Ural State University, 76 Lenin ave, Chelyabinsk 454080, Russian Federation.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kropotina
authors.affiliation: Chemistry Department, South Ural State University, 76 Lenin ave, Chelyabinsk 454080, Russian Federation.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Muhitdinova
authors.affiliation: Quantum Chemistry, Mendeleev University of Chemical Technology of Russia, 9, Miusskaya Square, Moscow 125047, Russian Federation.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tsirelson
keywords: Laplacian of electron density; electron localization function; iodine halogen bond; one-electron potential; quinolinium polyiodide