Description:
<jats:title>Abstract</jats:title>
<jats:p>We analyse rovibrational transitions of the (2)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup>–<jats:italic>X</jats:italic>(1)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup> system of LiSr and find the energy levels of the (2)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup> state to be perturbed by coupling between the (2)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup> and (1)<jats:sup>2</jats:sup>Π states. We present an analysis of the coupled system yielding molecular parameters for the lowest vibrational levels of the (2)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup> state and for higher vibrational levels of the (1)<jats:sup>2</jats:sup>Π state together with molecular coupling constants. Improved Dunham coefficients for the rovibrational levels of the <jats:italic>X</jats:italic>(1)<jats:sup>2</jats:sup>Σ<jats:sup>+</jats:sup> state are also obtained, where the correlation with the parameters of the excited states is removed completely.</jats:p>