DISSOCIATIVE SCATTERING OF MOLECULAR BF+ AND BF2+ IONS FROM AU SURFACES

Dissociative scattering of molecular BF+ and BF2+ ions from a polycrystalline Au surface has been investigated in the incident energy range of 10 to 200 eV with a polar incident angle of 45-degrees and a scattering angle of 90-degrees. The energy distributions of dissociative ion fragments and survival molecular ions were measured by means of a quadrupole mass spectrometer equipped with a cylindrical mirror energy analyzer. The measured distributions show an onset beam energy of 35 eV for BF+ dissociation and 20 eV for BF2+ dissociation. The experimental results, when compared with the theoretical data from a classical collisional approach, suggest a high probability of dissociation via vibrational excitation during collision. The lack of any strong antibonding states in BF+ and BF2+ which can receive electrons from the valence band of gold further indicates the unlikeliness of dissociation via an electronic process such as dissociative attachment.