High-efficiency surface-induced dissociation on a rhenium oxide surface

We report on the high-efficiency surface-induced dissociation of benzene and cyclohexane polyatomic ions after scattering from a rhenium oxide surface with a kinetic energy of 5-290 eV. Rhenium oxide was prepared by directly heating a rhenium metal foil, under 10(-5) mbar partial oxygen pressure, at about 1000 K.Rhenium oxide is characterized by a very high work function of 6.4 eV and thus minimizes ion reneutralization probabilities. The catalytic combustion of surface organic impurities with oxygen ensures good long-term stability.We found that the surface-induced dissociation ion current is 70 times larger on rhenium oxide than on bare rhenium or stainless steel. Absolute scattered ion yields of about 50% were measured. The implications of surface-induced dissociation on mass spectrometry in supersonic molecular beams are mentioned.