<p>We
have re-evaluated the X40x10 benchmark for halogen bonding using conventional
and explicitly correlated coupled cluster methods. For the aromatic dimers at
small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause
substantial reductions in the dissociation energy. For the bromine and iodine species,
(n-1)d subvalence correlation increases dissociation energies, and turns out to
be more important for noncovalent interactions than is generally realized. As
in previous studies, we find that the most efficient way to obtain HLCs is to
combine (T) from conventional CCSD(T) calculations with explicitly correlated
CCSD-F12–MP2-F12 differences.</p>
Halogen Bonding Between Anions: Association of Anion Radicals of Tetraiodo‐
p
‐benzoquinone with Iodide Anions
