Rotational excitation of HF in slow collisions with He

Low-energy rotational-excitation cross sections have been calculated from model-potential surfaces constructed to represent the interaction of atomic helium with hydrogen fluoride (HF). Quantum-mechanical solutions of the coupled equations were obtained including as many rotational states (open and closed) as needed for convergence. The behavior of the cross sections as a function of energy and the sensitivity to various model-potential surfaces are discussed.