| Mutual orientation of reagents is second only to the energy requirement for a chemical reaction to take place. Since the introduction of the hexapole field focusing and orientation of symmetric-top molecules in 1965, considerable insight has been gained on the role of orientation in reactive scattering dynamics. The degree of laboratory orientation has been measured for (CH{dollar}sb3{dollar}){dollar}sb3{dollar}CBr and has been found to follow the sequence (CH{dollar}sb3{dollar}){dollar}sb3{dollar}CBr {dollar}>{dollar} (CH{dollar}sb3{dollar}){dollar}sb3{dollar}CI {dollar}>{dollar} CH{dollar}sb3{dollar}I for previous measurements.; Oriented molecule beams of thirteen different molecules have been scattered by a graphite(0001) surface. The results show a large diversity in the sign and magnitude of the steric effect (i.e., "heads" vs. "tails"). It appears from the bulk of data that the origin of the steric effect is the anisotropic molecule-graphite interaction potential, which is governed by the charge density distribution of the molecule. The steric effects have been quantitatively measured for seven of the molecules and have been analyzed in terms of a two component model which yields estimates for the anisotropy of the trapping probability.; An effusive oven of Sr was used in a crossed beam reaction of Sr + CH{dollar}sb3{dollar}I. In order to detect weak product signal, a sensitive detection technique utilizing single photon ionization of the reaction product was developed. By changing the relative velocity of the reactants, the excitation function (reactive cross section vs. collision energy) was measured. The experimental results were simulated by a modified angle dependent line-of-centers model, which gives the reaction potential energy surface. Excitation functions of other alkyl halides reactions, Sr + RX (R = H, CH{dollar}rmsb3, Csb2Hsb5,Csb3Hsb7, Csb4Hsb9;{dollar} X = Br, I), were also explored. |
