High-resolution laser spectroscopy of the A ← X transition of LiAr

The rotationally resolved absorption spectrum of LiAr due to the transition A2Π ← X2Σ has been investigated by laser spectroscopy producing the molecules in a supersonic jet beam. Vibrational levels with ν = 0,…, 3 and ν = 5,…, 9 have been observed up to now for the X2Σ and the A2Π state, respectively. The XΣ interaction potential has been determined by means of a quantum mechanical method using a Hartree-Fock dispersion function. For the well-depth and equilibrium distance of XΣ. we obtain De = 42.5(1.2) cm−1, Re = 4.888(15) Å. Our preliminary results for the A2Π state are: De = 925(40) cm−1, Re = 2.48(6) Å.