The AΣu+1 state of K2 up to the dissociation limit

We report an experimental study of the K2 AΣu+1 state. Long-range levels up to the dissociation limit were observed in a two laser spectroscopic experiment using a highly collimated molecular beam. We derive an analytical potential energy curve for the complete A state including long-range dispersion terms. From these, we obtain radiative atomic lifetimes of 26.74(3)ns for the 4p1∕2 state and 26.39(3)ns for the 4p3∕2 state of K39. The dissociation energy of the XΣg+1 ground state with respect to v=0, J=0 is found to be D0=4404.808(4)cm−1.