A self-consistent kinetic model is developed to study dc flowing glow discharges in N/sub 2//O/sub 2/ mixtures. This model includes the calculation of electron energy distribution functions and electron rate coefficients coupled with detailed vibrational kinetics of N/sub 2/ molecules, chemical kinetics taking into account a large set of neutral, excited and charged species, interaction of N and O atoms at the discharge tube wall, and the thermal balance of the discharge. The results of this model agree reasonably well with the measurements of the electronic density, the gas temperature, the reduced electric field, the vibrational temperature of N/sub 2/ and the concentration of O, N atoms, NO molecules, N/sub 2/(C), N/sub 2//sup +/(B), and NO(/spl gamma/) excited states. The comparison was performed in a N/sub 2/-O/sub 2/ discharge at pressure p=2 Torr, for discharge currents I=15, 30, and 80 mA, a flow rate Q=100 sccm, and O/sub 2/ percentages ranging from 0 up to 100%,. >

Kinetic model of a low-pressure N/sub 2/-O/sub 2/ flowing glow discharge

A tomographic inversion is used to analyze measurements of the auroral atomic oxygen emission line at 6300 A made by the atmosphere explorer visible airglow experiment. A comparison is made between emission altitude profiles and the results from an electron transport and chemical reaction model. Measurements of the energetic electron flux, neutral composition, ion composition, and electron density are incorporated in the model.

The auroral 6300 Å emission: Observations and modeling

A self-consistent model of the global mean structure of the thermosphere is used to examine the ionospheric and thermospheric processes that control the structure of the thermosphere for solar minimum and maximum conditions during geomagnetic quiet periods. The model includes the physical and chemical processes believed to be dominant in the thermosphere and ionosphere. The total solar energy input available in the extreme ultraviolet and in the Schumann-Runge continuum portion of the solar spectrum is 14.1 x 10 to the 11th W and 21.5 x 10 to the 11th W for solar minumum and maximum, respectively. The calculated exospheric temperature is too small if maintained only by radiative processes, and an auroral heat source is necessary to bring the calculated global mean structure into agreement with the MSIS-83 empirical model for both solar minimum and maximum conditions. These results support the consensus that there is high-latitude heat source present at all times.

On the global mean structure of the thermosphere

1 Introduction 2 Experimental methods 3 Theoretical methods 4 The H2+molecule 5 Diatomic hydride ions 6 Diatomic ions 7 The H3+ molecule 8 Polyatomic ions 9 Related processes 10 Applications

/pdf/dissociative-recombination-of-molecular-ions-3m85661sw7.pdf

Dissociative Recombination of Molecular Ions

We review the gas-phase chemistry in extraterrestrial space that is driven by reactions with atomic and molecular ions. Ions are ubiquitous in space and are potentially responsible for the formation of increasingly complex interstellar molecules. Until recently, positively charged atoms and molecules were the only ions known in space; however, this situation has changed with the discovery of various molecular anions. This review covers not only the observation, distribution and reactions of ions in space, but also laboratory-based experimental and theoretical methods for studying these ions. Recent results from space-based instruments, such as those on the Cassini-Huygens space mission and the Herschel Space Observatory, are highlighted.

https://iopscience.iop.org/article/10.1088/0034-4885/75/6/066901/pdf

Ion chemistry in space

The total cross section as a function of electron energy for recombination of electrons with room temperature NO+ has been measured with a trapped ion technique. Measurements were made in the electron energy range 0.045–4 eV with an energy resolution between 0.045 and 0.120 eV, and the cross sections, which showed some structure, ranged from 1.25 × 10−14 cm² at the lowest energy to 1.7 × 10−16cm² at the highest energy. Similar measurements were made on O2+, the species used to calibrate the apparatus geometry. A Maxwellian distribution of electron velocities was used with the measured cross sections to calculate rate constants, giving values extending to electron temperatures as high as 40,000°K. Comparison with previously measured rate coefficients at lower temperatures is quite satisfactory.

G. H. Dunn

Papers

Measurement of total cross sections for electron recombination with NO+ and O2 + using ion storage techniques