The [557]-X²∑⁺ and [561]- X²∑⁺ bands of ytterbium fluoride,¹⁷⁴YbF

The [557] - X2Σ+(v = 0, 1, 2, 3) and the [561] - X2Σ+ (v = 2) visible electronic transitions of YbF have been recorded at a near-natural linewidth spectral resolution using both supersonically cooled and buffer-gas cooled beams. The 174YbF isotopologue spectral features were analyzed to produce a new set of spectroscopic parameters for the X2Σ+(v = 2), X2Σ+(v = 3), [557], and [561] states. This study will facilitate ongoing work to produce ultracold YbF molecules by laser cooling in order to improve measurements of the electron’s electric dipole moment.