  Medium resolution ($\Delta \nu$ ~ 3 GHz) laser-induced fluorescence (LIF)
excitation spectra of a rotationally cold sample of YbOH in the 17300-17950
cm$^{-1}$ range have been recorded using two-dimensional (excitation and
dispersed fluorescence) spectroscopy. High resolution ($\Delta \lambda$ ~ 0.65
nm) dispersed laser induced fluorescence (DLIF) spectra and radiative decay
curves of numerous bands detected in the medium resolution LIF excitation
spectra were recorded. The vibronic energy levels of the $\tilde{X} \,
^2\Sigma^+$ state were predicted using a discrete variable representation
approach and compared with observations. The radiative decay curves were
analyzed to produce fluorescence lifetimes. DLIF spectra resulting from high
resolution ($\Delta \nu$ < 10 MHz) LIF excitation of individual low-rotational
lines in the $\tilde{A} \, ^2\Pi_{1/2}(0,0,0) - \tilde{X} \,
^2\Sigma^+(0,0,0)$, $\tilde{A} \, ^2\Pi_{1/2}(1,0,0) - \tilde{X} \,
^2\Sigma^+(0,0,0)$, $[17.73]\Omega=0.5(0,0,0) - \tilde{X} \, ^2\Sigma^+(0,0,0)$
bands were also recorded. The DLIF spectra were analyzed to determine branching
ratios which were combined with radiative lifetimes to obtain transition dipole
moments. The implications for laser cooling and trapping of YbOH are discussed.
