Energies of the6snfF31,F23, andF33Rydberg states in Ba I

Abstract
We have determined accurate values for the energy of the 6snfF31,6snfF23 and 6snfF33 states of Ba I with principal quantum number n ranging from 13 to 45, using laser—atomic-beam spectroscopy. The experimental level energies for the thus-far-unknown F31 Rydberg series compare well with predicted values from hyperfine-structure measurements in the 6snfF2,33 series for n>30 and from Stark-effect studies in the 6sndD21 series.