Multiply-charged ions produced from condensed gas targets under heavy ion impact: comparison between atom and molecule targets

Multiply-charged secondary ions produced from condensed gas targets have been observed under energetic, heavy-ion impact. It is found that, though strongly suppressed over gaseous target collisions, multiply-charged ions are more efficiently extracted from condensed surfaces if molecules such as N2, O2, C2H2 are used as targets, compared with condensed rare-gas atom and other molecule (for example, CH4) gas targets. This feature could be understood qualitatively as being due to their large initial kinetic energy provided through Coulomb explosion of multiply-charged molecular ions originally produced in heavy-ion collisions. (Author)