An accurate helium-benzene interaction potential

Light atoms such as helium adsorbed on atomically thin substrates provide a rich platform for exploring exotic quantum many-body phenomena, owing to the highly tunable and atomic-scale nature of their interactions. However, the emergent physics depends sensitively on the detailed form of the adsorbate–adsorbent potential. To advance the development of accurate adsorption interaction models for two-dimensional systems, we present a benchmark study of helium interacting with a single benzene molecule. By combining high-level coupled-cluster calculations [CCSD(T) at the complete-basis-set limit validated by CCSDT(Q)] with multi-fidelity Gaussian process regression, we construct a new potential energy surface with sub-kelvin accuracy. Quantum Monte Carlo simulations of helium clusters surrounding benzene at low temperature reveal qualitative differences in solvation structure and configuration compared with existing model potentials. We conclude by discussing the transferability of this approach to larger polycyclic aromatic hydrocarbons.