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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
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NASA NTRS1972

Measurements of recombination of electrons with H3O(plus)-(H2O)n series ions

Recombination coefficients of electrons with ions of the hydrated hydronium ion series (H3O(+))(H2O)n, where n = 0, 1, 2, 3, 4, 5, 6, were determined with a microwave afterglow/mass spectrometer apparatus. Afterglow measurements of electron density decays in helium-water vapor mixtures are correlated with the decay of mass-identified ion currents to the wall of the microwave cavity. By varying the temperature of the gas and the partial pressure of the water vapor in the mixture, different groups of hydronium series ions are made to dominate the afterglow.

Leu, M. T.↗
NASA NTRS1972

6300 A quantum efficiency of the recombination mechanism in the night-time F layer.

Simultaneous airglow and electron content measurements made at Hawaii are used to infer the number of 6300 and 6364 A quanta produced per electron lost in the nighttime F layer of the ionosphere. The equation of continuity of electrons is then solved numerically to obtain the electron density profile, and the amount of quenching is estimated. This leads to the number of excitations of O(super-1 D) per O2(+) recombination (epsilon). We find, for an exospheric temperature of 1100 K, epsilon is equal to 1.1 plus or minus 0.6, in good agreement with Zipf's laboratory measurement at 300 K.

Brown, W. E.↗
NASA NTRS1972

Radiative transition probabilities and recombination coefficients of the ion C IV.

Bound-bound and bound-free radiative transition probabilities, as well as radiative recombination coefficients of the ion C IV, are computed with a semi-empirical polarization potential method. The nonhydrogenic probabilities and coefficients are given for all bound states of the ion up to the principal quantum number n = 7.

Leibowitz, E. M.↗
NASA NTRS1971

Recombination luminescence in irradiated silicon - Effects of thermal annealing and lithium impurity.

Use of luminescence in irradiated silicon to determine the thermal stability of the defects responsible for the recombination. It is found that the defect responsible for the zero-phonon line at 0.97 eV has an annealing behavior similar to that of the divacancy and that the zero-phonon line at 0.79 eV anneals in a manner similar to the G-15 or K-center. Annealing at temperatures up to 500 C generates other defects whose luminescence is distinct from that seen previously. Addition of lithium to the material produces defects with new characteristic luminescence. Of particular importance is a defect with a level at E sub g -1.045 eV.

Johnson, E. S.↗
NASA NTRS1972

Kinetics of O/super 3P/ + CO + M recombination.

Measurement of rate coefficients over the temperature range from 250 to 370 K for the three-body recombination of O(super 3P) with CO. Earlier results at 300 K have been re-evaluated and were found to have been influenced by unknown impurities in the CO, which have now been removed by more elaborate purification methods. For CO as the third body, the rate constant is given by K = 6.5 x 10 to the minus 33rd exp (-4340 plus or minus 550/RT) cm to the 6th power per sq molecule per sec. For N2 and CO2, the 296 K rate constants are 2.3 and 6.2 x 10 to the minus 36th cm to the 6th power per sq molecule per sec, respectively.

Slanger, T. G.↗
NASA NTRS1972

Low temperature recombination and trapping analysis in high purity gallium arsenide by microwave photodielectric techniques

Some physical theories pertinent to the measurement properties of gallium arsenide are presented and experimental data are analyzed. A model for explaining recombination and trapping high purity gallium arsenide, valid below 77 K is assembled from points made at various places and an appraisal is given of photodielectric techniques for material property studies.

Khambaty, M. B.↗
NASA NTRS1973

Atomic recombination rate determination through heat-transfer measurement.

A theoretical and experimental demonstration is presented which shows that under suitable conditions the volume recombination coefficient can be determined by measuring the heat transfer rate into the wall of a cylinder through which a dissociated stream is passing. The experimental results obtained are in agreement with those of other investigators.

Park, C.↗
NASA NTRS1975

Dielectronic recombination and abundances near quasars

Major obstacles to determining certain elemental abundances associated with some quasars are (1) a lack of accurately measured helium line intensities, and (2) uncertainty about the extent to which dielectronic recombination, i.e. C(+3) + e(-) yields C(+2), is suppressed at the relevant gas and radiation densities. Some calculated results are presented in an attempt to reduce the latter obstacle.

Davidson, K.↗
NASA NTRS1976

Cooling and recombination processes in cometary plasma

The ion electron plasma in comets is examined for cooling processes which result from its interactions with the neutral coma. A cometary coma model is formulated that is composed predominantly of H2O and its decomposition products where electrons are cooled in a variety of processes at rates varying with energy. It is shown that solar plasma plus accumulated cometary ions and electrons is affected very strongly as it flows into the coma. The electrons are rapidly cooled and all but some 10% of the ions undergo charge exchange. Photodissociation of H2O is assumed where ion electron recombination is the dominant loss process.

Wallis, M. K.↗
NASA NTRS1975

Experimental study of the C/3P/ + N/4S/ + M yields CN/B 2Sigma+/ + M recombination

The kinetics of the CN violet band emission produced by the reaction of nitrogen with cynogen is investigated as a function of the densities of atomic carbon and atomic nitrogen and of total pressure. It is shown that CN is formed in a three-body recombination reaction from C and N atoms. The reactions studied have relevance to investigations of the chemistry of interstellar molecules.

Washida, N.↗
NASA NTRS1976

Recombination of NO/+/ in the ionosphere

Simultaneous nighttime measurements of ion and neutral concentrations and temperatures made by the Atmosphere Explorer-C satellite were used to determine the recombination rate coefficient of NO(+) as a function of electron temperature. The results agree in shape and absolute magnitude to within one standard deviation with those of Walls and Dunn (1974), indicating that NO(+) ions in the ionosphere may be in the ground vibrational state.

Torr, D. G.↗