Fine Structure in the Singlet Series of Mercury

Abstract

UP to the present no fine structure has been observed in the singlet series of mercury. In a recent communication to the Physical Society of London (Proceedings, August 1930) a description was given of the spectrum of mercury excited at low pressures by a high frequency electrodeless discharge. Amongst other effects it was found that the singlet series and intercombination lines due to transitions beginning on singlet levels, were strongly enhanced relative to the triplets. The line 6¹P₁ − 8¹S₀ was examined for fine structure with a Fabry-Perot interferometer and found to be single and so narrow (half width < 0.004 A.) as to render it of great value in interferometric work.