[en] Angular and energy distributions of scattered fragments have been measured at glancing angle incidence of MeV HeH⁺ ions on a clean (001) surface of SnTe crystal. The distributions show that the internuclear vectors between fragments tend to align with the beam direction. The alignment is explained in terms of a surface wake potential due to dynamic response of surface electrons to the charges of fragments. In addition, internal energy released at dissociation of the ion is derived. The energy is approximately a half of the Coulomb potential energy of He²⁺ and H⁺ at the ground state of molecular ion. (author)