Molecular-Beam Kinetics. I. Magnetic Deflection Analysis of Reactions of Li with Cl2, ICl, Br2, SnCl4, and PCl3

Abstract

Thermal energy crossed-molecular-beam studies have been made of the reactions of Li with Cl2, ICl, Br2, SnCl4, and PCl3. An inhomogeneous deflecting magnet between the collision zone and detector was used to distinguish elastic scattering of Li from reactive scattering of LiX. Approximate transformations of the measured laboratory angular distributions to the center-of-mass (c.m.) coordinate system have determined: (1) the total reaction cross sections QR; (2) the approximate product recoil energies E′; (3) the reactive attenuations of the wide-angle elastic scattering; and (4) the LiX product c.m. angular distributions. A procedure has been developed for the determination of values of QR which corrects for resolution effects introduced by broad parent alkali beam profiles. Values of Qr, E′, and reactive attenuations of wide-angle elastic scattering which are reported here for the Li-atom reactions correlate roughly with trends established in previous studies of the reactions of Na, K, Rb, and Cs. However, the observed LiX c.m. product angular distributions are broader and more complex than projections based on studies with the heavier alkali atoms might have predicted. These observations are interpreted in terms of the electron transfer mechanism, which has been applied in previous studies of reactions of the heavier alkali atoms, with the inclusion of a possible mass effect in the alkali-atom reaction dynamics.