Accurate intermolecular ground state potential of the He–BH van der Waals complex

The interaction potential of van der Waals He–BH (X1Σ) complex has been firstly studied by ab initio calculations using single and double excitation coupled cluster with perturbative triples correction CCSD(T) method. The full counterpoise method is applied to correct for the basis set superposition error. With the basis set of the aug-cc-pV5Z augmented with 33211 midbond functions, the CP-corrected interaction energies are determined for 216 configurations. The values are further fitted to a two-dimensional potential model by a two-step least squares procedure. Two minima are found on the potential energy surface. The global minimum corresponds to a skew T-shaped geometry with energy −34.4389 cm−1 at R = 6.04a0 and θ = 70.0°. The shallower minimum locates at R = 8.35a0 and θ = 180° with well depth −8.5511 cm−1. A saddle point with energy −7.80 cm−1 appears at R = 8.20a0 and θ = 132.0°.