DOI: 10.1140/epjd/e2004-00127-x THE EUROPEAN PHYSICAL JOURNAL D Rotational structures of long-range diatomic molecules

Abstract. We present a systematic understanding of the rotational structure of a long-range (vibrationally highly-excited) diatomic molecule. For example, we show that depending on a quantum defect, the least-bound vibrational state of a diatomic molecule with −Cn/rn (n> 2) asymptotic interaction can have only 1, 2, and up to a maximum of n − 2 rotational levels. A classification scheme of diatomic molecules is proposed, in which each class has a distinctive rotational structure and corresponds to different atom-atom scattering properties above the dissociation limit. PACS. 33.15.Mt Rotation, vibration, and vibration-rotation constants – 34.10.+x General theories and models of atomic and molecular collisions and interactions (including statistical theories, transition state, stochastic and trajectory models, etc.) – 03.75.Nt Other Bose-Einstein condensation phenomena – 03.75.Ss Degenerate Fermi gases