Fundamental Energy Levels of Neutral Promethium (Pm I)

Abstract

The spectrum of atomic promethium has been observed with a variety of light sources and spectrographs. The Zeeman effect has also been recorded. Analysis of the spectrum shows that the ground configuration of the neutral promethium atom is 4f ⁵6s ². The relative positions (in cm^-1) of the low levels of this configuration are: [Table: see text] This group represents all levels of 4f ⁵6s ² expected below 14,000 cm^-1. From these results the following values of interaction parameters and their estimated uncertainties have been inferred: ${\zeta }_{4f}=925\pm 20{\text{cm}}^{-1}{E}^3=510\pm 20{\text{cm}}^{-1}$ Data on 209 upper levels of even parity and 714 classified lines are given.

Keywords: Atomic spectroscopy; electronic energy levels; neutral atom; promethium; rare earth.