A Molecular Beam Study of the (0,0) A2Π<- X2Σ+ Band of CaF Isotopologues

This study presents an experimental determination of spectroscopic parameters for the less-abundant isotopologues ${}^{42}$CaF and ${}^{44}$CaF, alongside ${}^{40}$CaF, using high-resolution laser-induced fluorescence spectroscopy in a skimmed free jet expansion. We recorded spectra near the natural linewidth limit and derived spectroscopic constants for both the $X^2{\mathrm{\Sigma }}^{+}$ and $A^2\mathrm{\Pi }$ electronic states, including the fine and ${}^{19}$F magnetic hyperfine parameters. We also estimated the isotope amount ratio $r{(}^{44}\mathrm{C}\mathrm{a}{\mathrm{/}}^{40}\mathrm{C}\mathrm{a})$, demonstrating the potential use of optical spectroscopy for calcium isotope analysis.