The Penning ionization cross section of Ar* + CHCl3 crossed beam reaction is determined as the function of both molecular orientation and relative collision energy using oriented CHCl3 molecular beam and TOF measurement. We find that the steric opacity function at low collision energies is well correlated to the exterior electron density distribution of the CHCl3 molecular orbital that plays a key role in the electron exchange. At high collision energies, however, the reactivity along the molecular axis becomes favorable while the sideways approach on the other hand becomes unfavorable. The result of our ab initio calculation reveals that this collision energy dependence of the sideways approach shows clear discrepancy with the generally accepted propensity rule for repulsive interaction potential. We propose here that this discrepancy Can be ascribed to the dependent competition of product branching between Penning ionization and that neutral dissociation varies as collision energy.