Bound-bound state quantum wave packet dynamics in the intermediate coupling range:: The A 1Σu+ (0u+) and b 3Πu (0u+) system in Rb2 -: art. no. 173006

The real-time quantum dynamics of a wave packet confined to two coupled bound states at intermediate interaction strength is probed by experiment and calculations on the A 1Sigma(u)(+) similar to b(3)Pi(u) system in Rb-2 molecules. The general dynamics consists of rapid spreading out over the whole phase space. Particular conditions exist, however, under which the initial wave packet motion separates into two mesobatic trajectories with distinct frequencies. These diabatic or adiabatic hybrid trajectories are analogous to those responsible for longevity resonances in bound-unbound systems.