Excitation of Cd, Zn, and Sr by a beam of active nitrogen

Excitation of the electronic levels of Cd, Zn, and Sr is observed when these metal vapors collide with a thermal-energy, active nitrogen beam. The beam is extracted from a glow discharge in pure N2. The active beam component is inferred to be vibrationally excited N2 in the A 3Σ+u electronic state. The absolute relative intensity of the emission lines in each element was measured. The excitation rates of the Cd and Zn target levels were found to depend exponentially on their energies indicating an effective temperature of approximately 4000°K. We believe that this temperature is related to the vibrational temperature of the N2(A 3Σu+) states that excite Cd and Zn in energy transfer collisions. The excitation rates of the Sr levels did not show an exponential energy dependence, which is a result consistent with N2(A 3Σu+) as the active species. The potential of such an emission study as a sensitive beam diagnostic is noted.