Molecular beam pump/probe microwave-optical double resonance using a laser ablation source

The first successful pump/probe microwave-optical double resonance experiment using a laser ablation/reaction scheme for molecular beam production has been performed. Pure rotational transitions at frequencies up to 52 GHz have been recorded for the transient refractory compounds YF, YO, and SrOH at a resolution of <30 kHz [full-width at half-maximum (FWHM)]. The observed three lowest pure rotational transition frequencies of YF (X¹Σ ⁺) were analyzed to produce an improved set of rotational constants, B=8683.6156(11) MHz and D=0.007 521(74) MHz. The three lowest pure rotational transitions of SrOH (X²Σ⁺) were analyzed to give the spectroscopic parameters (in MHz), B=7470.8180(4), D=0.006 25(3), γ=72.706(1), γ_D=-0.0021 (2); b_F (H)=1.713(2) and c (H)=1.673(5). The proton magnetic hyperfine interactions were interpreted in terms of a molecular orbital description for the X²Σ ⁺ state.