Fragmentation of CH4in collisions with fast highly charged ions

摘要

Measurements of the production cross sections for singly charged molecular ions by high energy (1 MeV/amu) Fq+(q=4,6ndash;9), Siq+(q=5,6,8ndash;12), and Cq+(q=3ndash;6) projectiles incident on a CH4target are reported. Similar measurements for singly charged recoil ions are presented for H+(E=1ndash;11 MeV) projectiles incident on CH4. We observed good agreement between our proton results and earlier electron measurements. Theoretical calculations for the sum of the cross sections for production of all singly ionized CHnfragments from CH4are presented using the Born and Glauber approximations, and both calculated cross sections are in reasonable agreement with the measured cross sections. Production of CH+3, CH+2, CH+, and C+fragments is analyzed both as a function of projectile charge and projectile velocity. Deviation from quasiequilibrium theory is observed in the relatively small cross section ratios of C+and CH+to CH+4as a function of projectile charge.