Laser and Fourier transform spectroscopy of KCa

KCa was produced in a heatpipe oven and its thermal emission spectrum around 8900 cm${}^{-1}$ was recorded by a high resolution Fourier transform spectrometer. In addition, many selected transitions of this spectrum between deeply bound vibrational levels of the $\mathrm{X}(1{)}^2{\mathrm{\Sigma }}^{+}$ and $(2{)}^2{\mathrm{\Sigma }}^{+}$ states were studied using laser excitation to facilitate the assignment of the lines. The ground state is described for $v^{\mathrm{\prime }\mathrm{\prime }}=$ 0 - 5 and the $(2{)}^2{\mathrm{\Sigma }}^{+}$ state for $v^{\mathrm{\prime }}=0$ - 8 with rotational levels up to 175. For both states, Dunham coefficients, spin-rotation parameters and potential energy curves are derived.