Energy loss distributions of He+ ions after collisions with HF molecules in a secondary beam at laboratory collision energies in the range 25-50 eV show a regular structure indicating rotational excitation up to Delta J=35 with no clear evidence for vibrational excitation. The observed propensity for large Delta J transitions decreases with increasing collision energy but increases with increase in scattering angle. Three dimensional quasiclassical trajectory calculations using a potential energy surface based on the He+-Ne interaction at short range and a damped long range ion-dipole (quadrupole) interaction reproduce all the essential features of the experimental results.