The Isotope Effect in Band Spectra, III. The Spectrum of Copper Iodide as Excited by Active Nitrogen

Excitation of spectra by active nitrogen.—Band spectra of CuF, CuCl, CuBr, and CuI have been obtained by the action of active nitrogen on the vapors of Cu${\mathrm{F}}_2$, CuCl and Cu${\mathrm{Cl}}_2$, Cu${\mathrm{Br}}_2$, and CuI, using the method of Rayleigh and Fowler, as previously applied by them to CuCl. Certain additional heads are present in the red, probably due to CuO formed as a result of slight oxygen impurity in the active nitrogen, and then excited by the latter. The halide bands are unusually sharp. Probably excited ${\mathrm{N}}_2$ molecules, in "impacts of the second kind," put halide molecules into the various excited electronic states necessary for the emission of visible band spectra. Many impacts, however, result in dissociation of the halide molecule, as the iodine are line $\lambda 2062$ and over 80 lines of the copper arc spectrum were identified. The list of copper lines is exactly the same for CuCl as for CuI. Analogous results have been obtained with Pb${\mathrm{I}}_2$, Hg${\mathrm{I}}_2$, and Hg${\mathrm{Br}}_2$. Other reactions of active nitrogen are discussed.