Title: POST-INDUCTION KINETICS IN SHOCK INITIATED H$sub 2$-O$sub 2$ REACTIONS

A simple model is used to predict the fractionation of isotopes as a function of temperature via ion-molecule reactions. It is developed for reactions proceeding via a single intermediate, where the isotopic mixing is completed within the lifetime of the intermediate such that the reaction is under thermodynamic control. The fractionation efficiency is K/(K + 1) where K is the equilibrium constant of the isotope-exchange reaction. The model is applied to deuterium and Oxygen 18 fractionation via the prototypical reactions OH(-)+H2O and H3O(+)+H2O; satisfactory agreement is found with the data available for 300 K. The model is also applied tomore » Nitrogen 15 fractionation via N2H(+)+N2 and comparison is made with the data available for 80 K. The model predicts simply the fractionation efficiencies for such isotope exchange reactions at the temperatures of interstellar clouds (10-100K).« less

The H + N{sub 2}O and D + N{sub 2}O reactions have been investigated by using the high-temperature photochemistry (HTP) technique. Empirical fits to the pressure-independent rate coefficients yield k1(T) = 4.2 x 10 to the -10th to the -14th power exp(-2290 K/T)+ 3.7 x 10 to the -10th power exp (-8430 K/T) and K2 (T) = 3.5x 10 to the 13th power exp -3600 K/T + 5.3 x 10 to the 10th powder exp(9-9170 K/T) cc/molecule/s over the ranges 410-1230 and 450-1210 K, respectively. The pi precision of these results is better than 11% and the 95% accuracy limitsmore » are assessed at about + or - 25%. The kinetic isotope effect x(T) = k1(T)/k2(T) decreases from 2.2 at 450 K to 1.3 at 1200 K, behavior contrary to classical transition-state theory which predicts x(T) increasing with temperature. The data are qualitatively consistent with a rate-controlling step that is dominated by tunneling at the lower end of the temperature range.« less

Sources of experimental and correlated thermodynamic data for the systems CO/sub 2/ + NH/sub 3/ + H/sub 2/O, CO/sub 2/ + H/sub 2/S + H/sub 2/O, H/sub 2/S + NH/sub 3/ + H/sub 2/O, and CO/sub 2/ + NH/sub 3/ + H/sub 2/S + H/sub 2/O are presented . The types of data in this bibliography include: all types of equilibrium data, both equilibria in solution and vapor-liquid equilibrium data; enthalpies; heat capacities; and densities. 215 references.

Project 758, initiated in 1976, comprises an experimental program to generate phase equilibrium data on gaseous components with water. Prior to formulating the project, a literature survey reported in RR-36 was conducted to determine the extent and quality of existing data in the area. One conclusion resulting from the survey is limited data exist for water-hydrocarbon systems and their quality varies from average to poor. Therefore, an extensive data development program is envisioned. Initial efforts to develop an experimental method to acquire accurate data rapidly have proved unsuccessful to date, thus delaying data generation. Consequently, the data summarized in themore » ensuing RR-41 were obtained by established, classical techniques for measuring phase equilibria. With the exception of hydrogen sulfide, the four gaseous components studied in this investigation are related primarily to substitute gas production. However, investigations currently in progress or planned will include natural gas and associated components as well as substitute gas constituents with water. The ultimate goal of the project is to provide adequate data from which existing correlations capable of predicting water-phase equilibria may be improved significantly, or if desirable, new models may be developed. 3 references, 11 figures, 6 tables.« less

The elementary reactions occurring in an H/sub 2/-F/sub 2/ explosion are given with each vibrational level of H/sub 2/ and HF considered as a separate reacting species. Rate coefficients for all the elementary reactions are either estimated or calculated, and the major assumptions entering into the determination of each rate coefficient are given. The effect of non-Maxwell distributions in the translational energies of some of the species is estimated. For strong pulses of F atoms, the explosion is complete before any appreciable contribution to the rate is made by thermal dissociation of F/sub 2/ or H/sub 2/. (auth)