The coupled system (2)Σ and (1)Πof LiSr

We analyse rovibrational transitions of the (2)Σ–X(1)Σ system of LiSr and find the energy levels of the (2)Σ state to be perturbed by coupling between the (2)Σ and (1)Π states. We present an analysis of the coupled system yielding molecular parameters for the lowest vibrational levels of the (2)Σ state and for higher vibrational levels of the (1)Π state together with molecular coupling constants. Improved Dunham coefficients for the rovibrational levels of the X(1)Σ state are also obtained, where the correlation with the parameters of the excited states is removed completely. Supplementary material for this article is available online