Journal of Physics B Atomic Molecular and Optical Physics
The coupling of the X1Σ+and a3Σ+states of the atom pair Na + Cs and modelling cold collisions
O. Docenko, M. Tamanis, J. Zaharova, R. Ferber, A. Pashov, H. Knöckel, E. Tiemann
Abstract
The states X 1 Σ + and a 3 Σ + correlated to the ground-state asymptote of Na (3s) and Cs (6s) atoms have been experimentally investigated using high resolution Fourier-transform spectroscopy. The hyperfine splitting of the a 3 Σ + state levels is partially resolved. Transitions to asymptotic vibrational levels of the a 3 Σ + and X 1 Σ + states were recorded simultaneously. The joint evaluation of the data of both the a 3 Σ + and the X 1 Σ + states allows us to determine accurate potential energy curves of both electronic states. Coupled-channels calculations are finally applied for deriving long range dispersion parameters and the exchange contribution of the molecular potentials, yielding a reliable description of cold collisions between Na and Cs atoms in their two different hyperfine ground states. Scattering lengths and Feshbach resonances are predicted for selected quantum states.