Polarisability and light-shift constants for SrF and BaF

Determine the molecular constants required to compute off‑resonant optical light shifts and polarisabilities for strontium monofluoride (SrF) and barium monofluoride (BaF) in the X( v = 0 ) 2Σ ground state, including the components needed to parameterize the ac electric‑field interaction (e.g., scalar, vector, and tensor polarisability terms or equivalent molecule‑frame parameters), which are reported as absent from the literature.

Background

The DiPolMol-Py package computes rotational and hyperfine structure for 2Σ molecules and includes interactions with dc magnetic fields, dc electric fields, and far off-resonant optical fields. Accurate modeling of the ac Stark (light) shift requires molecular polarisability constants and related parameters for each species.

While constants for CaF are provided and sufficient for field-free, Zeeman, and dc electric-field effects are available for SrF and BaF, the authors explicitly note that constants for the light shift and polarisability of SrF and BaF are not available in the literature. Obtaining these values is necessary to extend complete ac-field modeling to these species.