The visible laser excitation spectrum of YbOH: The Ã 2Π–X2Σ+ transition

The à 2Π–X̃ 2Σ+ electronic transition of YbOH has been analyzed for the first time. Gas-phase YbOH was produced in a Broida-type oven by the reaction of ytterbium metal vapor with H2O2 vapor. Low-resolution spectra recorded with a broadband dye laser were used to examine the vibrational structure of the ÖX̃ system while high-resolution laser spectroscopy with a single-frequency dye laser was employed to obtain spectra of the 000–000 and 000–100 bands of YbOH174 and the 000–000 band of YbOH172 (where v1 is the Yb–O stretching mode). The rotational analysis of the à 2Π–X̃ 2Σ+ transition demonstrates YbOH is a linear molecule, much like the alkaline–earth monohydroxides. Rotational and vibrational parameters are presented and the unusual behavior of the ground state spin-rotation splitting is discussed through a comparison with the isoelectronic molecule YbF.