The visible laser excitation spectrum of YbOH: The (A)over-tilde(2)Pi-(X)over-tilde(2)Sigma(+) transition

The (A) over tilde (2)Pi-(X) over tilde (2)Sigma (+) electronic transition of YbOH has been analyzed for the first time. Gas-phase YbOH was produced i n a Broida-type oven by the reaction of ytterbium metal vapor with H2O2 vap or. Low-resolution spectra recorded with a broadband dye laser were used to examine the vibrational structure of the (A) over tilde-(X) over tilde sys tem while high-resolution laser spectroscopy with a single-frequency dye la ser was employed to obtain spectra of the 000-000 and 000-100 bands of (YbO H)-Yb-174 and the 000-000 band of (YbOH)-Yb-172 (where v(1) is the Yb-O str etching mode). The rotational analysis of the (A) over tilde (2)Pi-(X) over tilde (2)Sigma (+) transition demonstrates YbOH is a linear molecule, much like the alkaline-earth monohydroxides. Rotational and vibrational paramet ers are presented and the unusual behavior of the ground state spin-rotatio n splitting is discussed through a comparison with the isoelectronic molecu le YbF. (C) 2001 American Institute of Physics.