Abstract by Andrew Arslanian
Chemistry and Biochemistry
Dependence of CRAFTI cross-sections on ion-neutral center-of-mass kinetic energy and ion dissociation energy
The cross sectional areas by Fourier transform ion cyclotron resonance (CRAFTI) technique depends on single, hard-sphere collisions to dephase coherent ion motion. CRAFTI cross sections are generally observed to increase with center-of-mass kinetic energy in a given collision gas, asymptotically approaching a value consistent with ion mobility measurements. We believe most dephasing occurs due to collision-induced dissociation. If this is true, the energies required to approach the asymptotic cross section will depend strongly on the energy required to dissociate the ions. In this study, we computationally and experimentally examine ions with different dissociation energies using various collision gases to probe the relationship between dissociation thresholds and asymptotic cross sections. Preliminary results indicate that, for similar ion species such as 12-crown-4/alkali metal guest, as bond dissociation threshold decreases the asymptotic collision cross-section is reached at lower energies.