Transients in Rapid Reactions by Combined Molecular Beam-Mass Spectrometric Analysis.

摘要

A novel technique for detecting and monitoring the concentration of transient intermediates in rapid gas-phase reactions has been developed and employed in studies of gaseous halogen chemistry and electric discharge chemistry. The technique, termed molecular beam analysis, combines mass spectrometry of ions with molecular beam characterization of neutrals prior to ionization, in order to achieve unambiguous identification of intermediates in gaseous reactions. In favorable cases, a sensitivity of 10 to the 11th power/cu cm has been attained. Using a steady-state flow-tube reactor, molecular beam analysis has been employed for kinetics studies of the reactions of F with CC14, CF3I, CC13Br and CF3Br; of C1 with HC1 and of Br with F2. Additionally, chemiluminescence generated in reactions of atomic fluorine was surveyed, and that in the combination reaction of H with F studied in detail. A gas phase titration for fluorine atoms was developed and used in a measurement of the rate constant for homogeneous recombination of fluorine atoms. Weak rf discharges were evaluated as sources of reactive intermediates for kinetic studies. (Author)