State-Resolved Reaction Dynamics
Final technical rept. 1 Dec 91-31 May 98
STANFORD UNIV CA DEPT OF CHEMISTRY
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Reactions of state-selected ammonia cation with D2, D2O, and CD4 were studied using a guided-ion beam instrument. The influence of vibrational and collision energy on these reactions was investigated by measuring cross sections for reaction of NH3 created with varying degrees of excitation in the umbrella bending- and symmetric stretching-modes. A comparison of the product cross sections from NH3 created in two states of nearly identical internal energies, but different concerted atom motions indicated that none of these reactions is mode-selective. The state-to-state ion-molecule reaction ND3 D2O -- ND4 OD was investigated. Rotational distributions were determined for the fine-structure states of the OD product for the reaction of vibrationally excited reactant ion. We also studied the proton transfer channel for the reaction of HBr with HBr. We developed two approaches exploiting optical laser sources to diagnose specific chemical species present in hostile environments In particular, cavity ring-down spectroscopy and two-photon light induced fluorescence were deployed to detect potential reactants present in a hot-filament chemical vapor deposition system used to grow diamond films. Finally, we used quadrupole mass spectrometry to detect the diatomic dications BaX2 XF, Cl, Br, I, SrCl2, CaBr2, and MgBr2.
- Physical Chemistry