THE $A^{2}\Pi - X^{2}\Sigma^{+}$ TRANSITION IN YTTERBIUM MONOFLUORIDE:

Abstract

High resolution excitation spectra of several isotopomers of YbF have been obtained using a single frequency ring dye laser. The previous analysis of Barrow and $Chojnicki^{1}$ has been extended beyond the $0-0$ transition. The $0-0$ band has been obtained at sub-Doppler resolution using Intermodulated Fluorescence. The results of the analysis will be presented including a discussion of A-doubling in the $^{2}\Sigma^{+}$ state, spin-rotation structure in the $^{2}\Sigma^{+}$ state and hyperfine structure. The correlation of the results with ligand field theory predictions will be discussed.