Cross sections for charge transfer reactions between ions and neutral atoms and molecules have been measured in the energy range from 50 to 850 ev. Charge transfer cross sections for symmetrical reactions in monatomic and diatomic gases increase with increasing viscosity cross sections. The charge transfer cross sections decrease with increasing incident ion energy in conformity with the adiabatic criterion. For reactions in diatomic gases the charge transfer cross sections decrease as the changes in internuclear distance for the processes increase.

Metastable resolved recombination, ionization and emission coefficients of impurity ions in thermal plasmas AIP Conf.The visible emission from electronically excited N02 has been studied both with thermal excitation in an electric oven and with recombination excitation from the nitric oxide-atomic oxygen reaction. In both cases the emission is continuous with weaker, diffuse bands superimposed. The correlation of these bands with N02 absorption bands has been extended. The thermal emission continuum begins near 3300 A and increases in intensity to the end of our range at 8600 A. The recombination emission continuum begins near 3800 A and has a broad maximum at 6200 A, in general agreement with previous workers. The absolute intensity of the thermal emission has been obtained at 100-A intervals between 4600 and 8600 A for temperatures between 972 and 1335°K. Excitation energies, which are obtained from the variation of intensity with temperature, range from 66 kcal at 4600 A to a minimum of 44±1 kcal near 8300 A. This latter value is Eo, the minimum energy of the emitting state of N02• Radiative lifetimes are obtained for thermal emission which range from 100 to 1 J.Lsec depending on emission wavelength and which approximately agree with fluorescent lifetimes for comparable excitation energies. The results are compared with shock tube measurements and are discussed in relation to air emissivity and opacity problems.If the choice is limited to quadratic forms, it is impossible to find representations of quantum states by positive distributions on phase space, either in the ordinary or in an extended "coarse-grained" sense.

The method utilized by the authors for determining charge transfer cross sections has been improved and applied to symmetric and unsymmetric reactions involving the inert gases, N2, H2, CH4, C2H4, C2H6, and C3H8. The cross sections were found to be about 20% higher than the values previously reported. The discrepancy can be explained by the fact that in previous experiments cross sections were determined from net charge measurements without taking full account of the secondary electrons impinging on the plate where the charge transfer ions were collected. As expected from adiabatic hypothesis, the reactions involving mixtures of gases having nearly equal ionization potentials were found to have maximum cross sections for low-energy ions. The interaction distances were calculated from the observed ion energy for which the cross sections are a maximum. The method described here can be utilized to determine the secondary electron emission from a metal surface due to ion bombardment. Such determination has been made for a brass surface. Relating the variation of emission with the ion mass and energy, it is found that the emission varies inversely as the square root of the ion mass.

No abstract

Cross sections are measured for excitation of the (0, 0) first negative band by protons in the range 5000 to 25,000 ev and by electrons in the range 45 to 25,000 ev. Upper limits are given for the very weak proton excitation of the first and second positive systems. To find the cross sections for the primary collisions and to avoid secondary effects, measurements are extrapolated to zero pressure. Not all intensities emitted are proportional to the pressure. The processes responsible for these deviations, excitation by neutral atoms and collisional deactivation, are investigated.