The total secondary electron emission yields from a clean (001) surface of SnTe crystal are studied at the bombardment of hydrogen clusters (H + , H + 2 and H + 3 ions) with energies ranging from 7 to 12 keV/amu. The observed yield is not proportional to the number of protons in the cluster ion. The yields are successfully explained by applying the stopping powers of a homogeneous electron gas for the constituents of the clusters in keV energy region, which provide the vicinage effect.