Molecular Dissociation Produced by Fast Heavy Ion Bombardment

A technique has been developed to study the dissociative ionization of molecules by fast, heavy ions. A pulsed beam of projectiles is focused into a differentially-pumped chamber containing a gaseous, molecular target. The fragment ions from the molecular target are investigated by measuring their kinetic energy and their time-of-flight (TOF) from the collision region to a detector. The simultaneous measurement of kinetic energy and TOF separates the fragments according to their mass-to-charge ratios and yields the kinetic energy spectrum of each. This time-energy spectroscopy method has been applied to several diatomic molecules and methane. Dissociative states of molecules and ionizing collisions by different projectiles have been investigated.