Laser and Fourier-transform spectroscopy of KCa

Abstract

KCa was produced in a heat-pipe oven and its thermal emission spectrum around $8900\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ was recorded with a high-resolution Fourier-transform spectrometer. In addition, many selected transitions of this spectrum between deeply bound vibrational levels of the $X{(1)}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ and ${(2)}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ states were studied using laser excitation to facilitate the assignment of the lines. The ground state is described for ${v}^{\ensuremath{'}\ensuremath{'}}=0--5$ and the ${(2)}^{2}{\mathrm{\ensuremath{\Sigma}}}^{+}$ state for ${v}^{\ensuremath{'}}=0\ensuremath{-}8$ with rotational levels up to 175. For both states, Dunham coefficients, spin-rotation parameters, and potential energy curves are derived.