The Spectrum of Lead Hydride

Abstract

From a lead arc in a hydrogen atmosphere at four to five atmospheres pressure, a "many-lined" spectrum in the region 5000-7000A due to PbH has been produced. Practically all of the lines have been assigned to ten bands constituting a $^{2}\ensuremath{\Sigma}\ensuremath{\rightarrow}^{2}\ensuremath{\Sigma}$ transition between an upper state of low stability and a stable ground state (${\ensuremath{\omega}}_{e}=1565.2$, ${B}_{e}=4.972$). Strong interaction with other states is evidenced by a very large spin-doubling ($\ensuremath{\gamma}=6.17$) in the lower state and in the upper state by an unorthodox variation of ${{B}_{v}}^{*}$ with $v$, irregular spin doubling, a prominent failure of the Mecke rule and a sharp cut-off of levels at about $\frac{1}{3}$ volt above ${K}^{\ensuremath{'}}=0$, ${v}^{\ensuremath{'}}=0$.