Binding in the Ar-I(2)(X(1)Σ(g)(+)) complex: a challenge for theory and experiment

New high-level ab initio calculations for ArI and ArI(2) are reported and compared with experimental data. For the directly calculated potential energy surface (PES), the bond dissociation energies D(0) values for both linear (L) and T-shaped (T) conformers of Ar-I(2) are found to be significantly larger (D(0)(L)≈197 and D0 (T)≈181 cm(-1) ) than deduced from recent experimental data. A further DIM-based correction is successfully tested for Ar-Cl(2) (the PES of which is shown in the picture) and predicts intervals D(0)(L)≈250±8 and D(0)(T)≈242±11 cm(-1) for Ar-I(2), which matches earlier experimental results.