The fine and magnetic hyperfine structure of ⁸⁷SrF in its X ²Σ⁺ state

A molecular beam rf-optical double resonance experiment was performed on ⁸⁷SrF in its naturally occurring abundance ratio. The natural occurring abundances of the strontium isotopes are ⁸⁶Sr (9.8%), ⁸⁷Sr(7.02%), and ⁸⁸Sr (82.5%). Numerous magnetic dipole allowed transitions between ρ-doublets in the X ²Σ ⁺ state were measured to an accuracy of 3 kHz. The observed spectra were analyzed in terms of an effective Hamiltonian which includes the magnetic hyperfine and electric quadrupole interactions arising from the ⁸⁷Sr (I = 9/2) and ¹⁹F (I = 1/2) nuclei. The extracted spectroscopic hyperfine parameters were interpreted in terms of a simple molecular orbital picture for the electronic nature of the X ²Σ⁺ state. A comparison is made to previous results for the more abundant ⁸⁶SrF and ⁸⁸SrF isotopic forms.