Photon and positive ion production from collisions of superthermal hydrogen atoms with lithium atoms and molecules. [1 to 10 eV, cross sections, emission spectra]

Photon and positive ion production from superthermal collisions of hydrogen atoms with lithium atoms and molecules is reported. These are the first results in the difficult 1 to 10 eV collision regime obtained with recently developed high intensity plasma-arc source of H atoms. These superthermal H atoms (approximately 5 eV average kinetic energy but not velocity selected in these experiments) have been collided with an intense supersonic lithium beam (approximately 10 percent Li/sub 2/; Li/sub 3/ undetectable) with cold internal degrees of freedom (T/sub vib/ = 195/sup 0/K, T/sub rot/ = 70/sup 0/K). The other aspects of the apparatus have been given previously. Low resolution photon and positive ion production in the collision chamber scattering center and also medium resolution; photon production in the magnet chamber between the skimmer and the magnet were detected

Li/Li/sub 2/ supersonic nozzle beam

The characterization of a lithium supersonic nozzle beam was made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li/sub 2/ can be described by a Boltzmann distribution with T/sub v/ = 195 +- 30/sup 0/K. The rotational temperature is found to be T/sub r/ = 70 +- 20/sup 0/K by band shape analysis. Measurements by quadrupole mass spectrometer indicates that approximately 10 mole per cent Li/sub 2/ dimers are formed at an oven body temperature of 1370/sup 0/K n the supersonic nozzle expansion. This measured mole fraction is in good agreement with the existing dimerization theory