Hyperfine Structures of the Resonance Lines of Indium (In115)

Abstract

In the process of developing an atomic beam light source for use at high oven temperatures an investigation of the indium resonance lines at 4511A and 4101A was carried out. The employment of a well-collimated atomic beam, excited by electron impact, and of a Fabry-Perot interferometer made it possible to resolve clearly all components of the hyperfine structures of both lines. The complete resolution of the line 4511A has not been accomplished with other light sources by other investigators. The high spectroscopic accuracy led to values of the hyperfine splittings of the $5{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2},\frac{3}{2}}^{}{}_{}{}^{}$ terms which agree within ±0.0004 ${\mathrm{cm}}^{-1\mathrm{}}$ with the values obtained by microwave methods. Furthermore, a precise value for the hyperfine splitting of the $6{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}$ term was obtained, namely 0.2814±0.0005 ${\mathrm{cm}}^{-1\mathrm{}}$.