Product magnetic deflection slotted disk velocity analysis molecular beams kinetics: Li+SnCl4, PCl3, and SF6

Recoil velocity spectra of the diamagnetic Li-containing products reactively scattered from crossed thermal beams of Li and SnCl4, PCl3, or SF6 have been measured by positioning a combination of an inhomogeneous deflecting electromagnetic and slotted disk velocity analyzer between the collision zone and detector. Transformation of these data into the center-of-mass coordinate system provides contour maps of the differential reaction cross sections. Although data on Li+SF6 are very noisy, they are consistent with a long-lived collision complex and energy equipartitioning in a loose transition state (LTS) mechanism. At some scattering angles, two peaks are observed in the measured product recoil spectra for both Li+SnCl4 and Li+PCl3. For Li+SnCl4, indirect kinematic arguments suggest that this bimodal structure is due to LiSnCl3+Cl and LiCl+SnCl3 product channels proceeding via an LTS mechanism. For Li+PCl3, this bimodal structure is attributed to production of LiCl+PCl2 products via an LTS and a direct mechanism. These results are discussed in relation to previous work on these systems and interpreted in terms of the electronic structure of the ion-pair intermediates.