Fluorescence branching ratios and magnetic tuning of the visible spectrum of SrOH

The magnetic tuning of the low rotational levels in the X̃2Σ⁺ (0,0,0), Ã2Π_r (0,0,0), and B̃2Σ⁺ (0,0,0) electronic states of strontium hydroxide, SrOH, have been experimentally investigated using high resolution optical field-free and Zeeman spectroscopy of a cold molecular beam sample. The observed Zeeman shifts and splittings are successfully modeled using a traditional effective Hamiltonian approach to account for the interaction between the Ã2Π_r and B̃2Σ⁺ states. The determined magnetic g-factors for the X̃2Σ⁺, Ã2Π_r, and B̃2Σ⁺ states are compared to those predicted by perturbation theory. The dispersed fluorescence resulting from laser excitation of rotationally resolved branch features of the 0₀ ⁰ B̃2Σ⁺←X̃2Σ⁺, 0₀ ⁰ Ã2Π_3/2←X̃2Σ⁺ and 0₀ ⁰ Ã2Π_1/2←X̃2Σ⁺ transitions have been recorded and analyzed. The measured fluorescence branching ratios are compared with Franck-Condon calculations. The required bending motion wave functions are derived using a discrete variable representation (DVR) method. Implications for laser slowing and magneto-optical trapping experiments for SrOH are described.