| A selected ion flow tube (SIFT) and a Flowing Afterglow (FA) with extensive spectroscopic facilities were used in the kinetic and dynamic studies of gas phase reactions between ions, electrons, and neutral atoms and molecules. Along with the interest, these reactions have importance in planetary atmospheres, interstellar gas clouds, circumstellar shells, comets, laser plasmas, combustion flames, and etchant plasmas.;SIFT studies of H3O+(H2O)0,1 reactions with sulfides and thiols were performed because of their significance as atmospheric pollutants and in molecular synthesis in interstellar gas clouds. The study shows that proton transfer and ligand switching with internal proton transfer are important mechanisms. Furthermore, it indicates that the proton affinities of n- and iso-propanethiol are larger than previously thought.;Using these and other data on H3O+ proton transfer reactions and our experimental determination of the first complete branching ratios for the dissociative electron-ion recombination of H3O +, a limited chemical model that predicts the H2O abundance in some of the giant interstellar molecular clouds was developed. The product distribution shows that the H2O channel is 7 times smaller than previously assumed and that fragmentation into three body channels is considerable. The model predicts an H2O abundance in good agreement with recent observations and that proton transfer to neutral species is a significant loss process for H3O+.;Dissociative charge transfer in reactions of CCl4 and SF 6 with common plasma ions was also investigated. Kinetic and product ion information was used in conjunction with photoelectron-photoion coincidence data, from the literature, to provide insight into the fragmentation of excited CC14+ and SF6+ ions. The degree of fragmentation and the energy thresholds at which product ions are observed are generally consistent with a long range mechanism in which the energy goes into fragmentation.;A technique for observing IR emissions from gas phase ionic reactions was developed. This method was proven by studying well-characterized neutral reactions and the associative detachment reaction of Cl- with H atoms. Excellent agreement of the vibrational product state populations was obtained with previous studies. Data acquisition times were reduced by a factor of four while resolution improved by an order of magnitude. |
