Path integral molecular dynamic study of nuclear quantum effect on small chloride water clusters of Cl−(H2O)1-4

► PIMD simulations with PM6-DH+ potential are carried out for Cl−(H2O)n clusters. ► The probability for single/multi shell structures is decreased/increased due to NQE. ► The ionic HB strength in the first hydration shell is increasing with cluster size. ► The correlations between δ and other vibration motions are discussed.