The Positive Ion Excitation of Mercury Vapor

Mercury vapor was bombarded by ${\mathrm{Li}}^{+}$ and ${\mathrm{K}}^{+}$ ions and the resulting spectra photographed with a quartz spectrograph and the plates photometered to give an approximate intensity-velocity curve. Voltages used ranged from 150 to 1500 volts. The results indicate that the velocity rather than the energy is the important factor to be considered in the mechanism of the collision process. A preference seems to exist for the excitation of levels of higher $L$ values. The spark lines 2847, 2260 and 2224 appear at 1000 volts for ${\mathrm{Li}}^{+}$ ions. A powerful source of positive ions has been developed.