Fine and hyperfine interaction in YbF 173

The fine and hyperfine interactions in X2ς+(v=0) and A2Π1/2(v=0) states of YbF173 have been characterized using a combination of high-resolution laser-induced fluorescence spectroscopy of the A2Π1/2-X2ς+ (0,0) electronic transition and ground-state microwave spectroscopy. Fourteen microwave transition frequencies associated with the N=3→N=4 and N=4→N=5 pure rotational spectra were recorded using a separated field pump-probe microwave optical double-resonance (PPMODR) scheme. Five transition frequencies associated with the N=0→N=1 rotational spectrum were recorded using Fourier transform microwave spectroscopy. A combined analysis of the A2Π1/2-X2ς+ (0,0) electronic transition and the pure rotational spectrum of the X2ς+ state has been performed to derive the molecular fine, magnetic hyperfine, and nuclear electric quadrupole moment parameters, e2Qq0, for Yb173(I=5/2). The determined e2Qq0 parameters are in agreement with a recent theoretical prediction [Mol. Phys. 114, 1110 (2016)10.1080/00268976.2016.1139206]. The determined Yb173 hyperfine parameters will be useful for the spectroscopic analysis of the YbOH173 molecule, which has been suggested [Phys. Rev. Lett. 119, 133002 (2017)10.1103/PhysRevLett.119.133002] for use in the magnetic quadrupole moment search.