Relativistic effects on halogen bonding

We decided to study relativistic effects on halogen bonding, because it has not yet been systematically and adequately investigated. The Benchmark Energy and Geometry Database contains a set of noncovalent complexes of halogenated molecules, from which we selected some complexes with Br and I atoms involved in halogen bonding. Bromine, and especially Iodine are heavy atoms, meaning that (scalar) relativistic effects could have non-negligible impact on molecular properties. The complexes that we chose include reasonably large organic molecules, such as formaldehyde, benzene, methanethiol or halogenated methane, which are feasible for systematic computational investigation with proper coverage of correlation and scalar relativistic effects. (authors)