Ionization Potential of Boron, and the Isotopic and Fine Structure of 2s2p^2 2D

Abstract

The nf ²F series (n = 4–11) of B i is found from combinations with 3d ²D and 2s2p^{2 2}D, and the series limit is derived by means of a Ritz formula, yielding an ionization potential of 66 928.10±0.1 cm⁻¹. The same value applies to both ¹⁰B and ¹¹B because the isotope shift of the ground state is shown to be zero. From the resolved structure of the transition 2s2p^{2 2}D–4f ²F at 8212 Å, we derive for 2s2p^{2 2}D a fine-structure interval of −0.31 cm⁻¹ and an isotope shift of −0.58 cm⁻¹, corresponding to a specific mass shift of −0.67 cm⁻¹.