摘要
We report on the state-selective detection of near-dissociation ultracold KRb molecules in the ground XΣ+1 state and the metastable aΣ+3 state. The molecules are produced by photoassociation of ultracold atoms followed by radiative decay into high vibrational levels of the X and a states. Detection utilizes resonance-enhanced one-color two-photon ionization, followed by time-of-flight mass spectroscopy. Scanning the detection laser frequency over the range 582-625nm, we observe transitions from the v″=86-92 levels of the X state, which are bound by up to 30cm-1, and the v″=17-23 levels of the a state, which are also bound by up to 30cm-1. The measured vibrational spacings are in excellent agreement with those previously measured and those calculated from the relevant potential curves. Relative vibrational populations are also consistent with Franck-Condon factors for decay from the photoassociated levels. © 2005 The American Physical Society.