The electronic system (2) ² ∑ ⁺ and (1) ² of LiCa

High-resolution Fourier transform spectroscopy and Laser-induced fluorescence have been performed on LiCa in the infrared spectral range. We analyse rovibrational transitions of the (Formula presented.)–(Formula presented.)  system of LiCa and find the (Formula presented.)  state to be perturbed by spin–orbit coupling to the (Formula presented.)  state. We study the coupled system obtaining molecular parameters for the (Formula presented.)  and the (Formula presented.)  state together with effective spin–orbit and spin–rotation coupling constants. The coupled system has also been evaluated by applying a potential function instead of rovibrational molecular parameters for the state (Formula presented.). An improved analytic potential function of the (Formula presented.)  state is derived, due to the extension of the observed rotational ladder.