Laser and Fourier transform spectroscopy of 7Li88Sr

LiSr was produced in a heat-pipe oven and its thermal emission spectrum around 9300 cm^-1 was recorded by a high resolution Fourier transform spectrometer. In addition, selected lines of the spectrum of deeply bound vibrational levels of the {1}²{{{Σ }}}⁺ and {2}²{{{Σ }}}⁺ states were studied using laser excitation to facilitate the assignment of the lines. The ground state could be described for {v}^{{\prime\prime} }=0 to 2, {N}^{{\prime\prime} } up to 105 and the {2}²{{{Σ }}}⁺ state for {v}^{\prime }=0 up to {N}^{\prime }=68. For both states, Dunham coefficients, spin-rotation parameters and potential energy curves were evaluated. A coupling of the {2}²{{{Σ }}}⁺ state to the {1}²{{\Pi }} state was observed, allowing a local description with Dunham coefficients of the {1}²{{\Pi }} state and an approximate evaluation of the coupling strength.