Assessment of Scalar Relativistic Effects on Halogen Bonding and $\sigma$-Hole Properties

摘要: Halogen bond (X-bond) is a noncovalent interaction between halogen atom and an electron donor. It often rationalized by region of the positive electrostatic potential on atom, so-called $\sigma$-hole. The X-bond strength increases with atomic number involved, thus for heavier halogens, relativistic effects become concern. This poses challenge quantum chemical description X-bonded complexes. To quantify scalar (SREs) energies $\sigma$-hole properties, we have performed highly accurate coupled-cluster calculations at complete basis set limit several complexes their halogenated monomers. SREs turned to be comparable in magnitude effect set. nonrelativistic typically underestimate attraction up 5% or 23% brominated iodinated complexes, respectively. Counter-intuitively, densities critical points are larger SRE-free than ones. yield smaller, flatter, more $\sigma$-holes. Finally, highlight importance diffuse functions sets provide quantitative arguments using pseudopotentials as affordable alternative rigorous Douglas-Kroll-Hess theory.