The electronic state of KLi molecule

The A 1 Σ + ← X 1 Σ + band system in the 39K7Li molecule is investigated by the polarisation labelling spectroscopy technique. The excited state is characterised by a set of Dunham coefficients describing rovibrational levels v = 0 – 34 , J = 9 – 73 and the corresponding potential energy curve is constructed with the Rydberg–Klein–Rees method. The main equilibrium constants are T e = 12097.11 ( 3 ) cm - 1 , (with respect to the minimum of the electronic ground state), ω e = 137.0821 ( 131 ) cm - 1 , R e = 3.9466 ( 3 ) Å .