Application of highly time-resolved coherent anti-Stokes Raman scattering to chemical dynamics

The first part of this dissertation reports the results of state-to-state dynamics experiments on the D + H2 → HD + H reaction as well as D + H2 → H2 + D energy transfer at relative energies of 0.67 eV and 0.79 eV. Both product state distributions and absolute partial cross sections have been determined from CARS spectra of the HD and H2 products recorded under single-collision conditions following pulsed laser photolysis of DI to generate the D atoms. At both energies and for both reactive and inelastic collisions there is a strong dynamical bias against rotational and vibrational excitation of the product. However, at 0.67 eV there is an enhancement of both the relative and absolute yield of HD (v' = 1) and to a lesser extent H2 (v' = 1), the only energetically accessible vibrationally excited product states. This may be the result of a Feshbach resonance at 0.66 eV, just above the v' = 1 threshold energy. The experiments are compared with the theoretical results of both close-coupled quantum calculations and quasi-classical trajectory calculations. The second part of this dissertation describes a method for deconvoluting incompletely resolved CARS spectra to obtain population distributions. No particular form for the population distributions is assumed, the population of each quantum state is treated as an independent variable. The method of analysis reported here has been developed to deconvolute CARS spectra of photofragments and chemical reaction products obtained in chemical dynamics experiments under non-equilibrium conditions. The deconvolution procedure has been incorporated into a computer code that is listed in an appendix. The application of that code to the deconvolution of CARS spectra obtained for samples at thermal equilibrium and not at thermal equilibrium is reported