Accurate ground state potential of Cs2 up to the dissociation limit

Abstract

Using the method of Doppler-free double resonance polarization spectroscopy transitions from selectively pumped levels (v′, J′) of the D1Σ+u state down to levels (v″, J″) of the X 1Σ+g state with v″= 0–140 have been measured with high accuracy. A long range analysis, based on 21 outer turning points of the IPA potential with v″=110-130 and on calculated exchange energies and second order van der Waals coefficients Cn with n=6, 8, 10, and 12 leads to a dissociation energy De =3649.5±0.8 cm−1 (0.452 49 eV). The influence of the third order C11 contribution and the hyperfine structure on the correct value of De are briefly discussed.