Physisorption of helium on a TiO2(110) surface: Periodic and finite cluster approaches

► He/TiO2(110) is a simplest example of physisorption on transition-metal oxide surfaces. ► Optimized basis sets that minimize the BSSE are better suited for physisorption problems. ► FCI benchmarks on the He2 bound-state assess the Counterpoise scheme reliability. ► Periodic DFT-PBE and post-HF results on H-saturated clusters compare satisfactorily. ► Correlation energies by using embedded and H-saturated clusters agree well.