^3S_1 Hyperfine-Structure Separations and Isotope Shifts of Radioactive Cd^107, Cd^109, and of Stable Cd Isotopes*

Abstract

High-resolution spectra of radioactive Cd¹⁰⁷ (6.7 h) and Cd¹⁰⁹ (470 days), and of Cd¹¹¹ and Cd¹¹³ were obtained in the wavelengths λ=3261, 4678, 4800, and 5085 Å with the use of a 10-in. well-blazed plane diffraction grating mounted in the two-mirror (multiple-wavelength) monochromator of 40-ft focal length. The radioactive Cd¹⁰⁷ and Cd¹⁰⁹ were produced by bombarding natural silver foil with deuterons. The Cd¹¹¹ and Cd¹¹³ electrodeless lamps were prepared from separated isotope samples. We find: Cd¹⁰⁹–Cd¹¹³ isotope shift in the 3261-Å resonance line, 0.033±0.005 cm⁻¹, with the sign of the volume-dependent isotope shift, and hfs separation in the 5s6s ³S₁ state, Δν(Cd¹¹³)=−0.407±40.005 cm⁻¹. (The single previously quoted value was obtained with natural Cd.) The three 5s6s to 5s5p ³P lines display isotope shifts that are smaller than the precision of the experiment. A factors of Cd¹⁰⁷, Cd¹⁰⁹, and Cd¹¹¹ are obtained from the spectroscopic and the published resonance and level-crossing data. The isotope shift is studied in combination with the results of Kuhn and Ramsden, and those of Brix, Steudel, and Blaise, in the light of possible nuclear polarizability effects such as have been described by Tomlinson and Stroke in the case of mercury isotopes.