Analysis of the hyperfine structure of the mercury 6^3D_3 → 6^3P_2 transition*

Abstract

The 63D3 → 63P2 (3650 A) line of mercury has been fully analyzed using both conventional high-resolution photographic techniques and a piezo-electrically scanned Fabry–Perot spectrometer system with photoelectric detection. Pure and enriched isotope lamps were used to isolate and identify the transitions of the 199 and 201 isotopes and to measure the isotope shifts of the even-mass isotopes. Isotope shifts of 7 ± 1 mK per unit atomic mass were found. The 3/2–5/2, 5/2–7/2, and 7/2–9/2 energy differences in the 3D3 state of the 201Hg isotope are, respectively, 206 ± 2, 287 ± 3, and 367 ± 6 mK. The A and B nuclear-moment terms of this state for the 201 isotope are A = −81.8 ± 1 mK and B = +2.0 ± 0.4 mK. Computer fits of the Fabry–Perot spectra of natural mercury were attempted. All transitions fit predicted intensities except for the strong lines that significantly overlap with each other. Within this group of lines there is strong reabsorption. This is a direct consequence of the unique overlap of the most intense transitions caused by small isotope shift and the lack of radiative decay processes for depopulation of the lower state.