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We report the spectroscopic characterization of excited electronic states of KRb by combining spectra from molecular beam (MB) experiments with those from ultracold molecules (UM) formed by photoassociation (PA) of ultracold atoms. Spectra involving the 11Π, 23Σ+, and b3Π states in a strongly perturbed region have been identified. This approach provides a powerful method to identify the vibrational levels of the excited electronic states perturbed globally by neighboring electronic states. This is because the two sets of spectra from the UM and the MB experiments probe the same energy region from very different initial electronic states. The UM experiments utilize high v′′ levels of the a3Σ+state with large internuclear separations, while the MB experiments utilize low v′′ levels of the ground X1Σ+state with near-equilibrium internuclear separations. Only the Ω= 1 levels of the 23Σ+and b3Π states are observed in the MB spectra, while the Ω= 0−, 1 levels of the 23Σ+state and the Ω= 0±, 1, 2 levels of the b3Π state are observed in the UM spectra. [ABSTRACT FROM AUTHOR]

Because of the long-range behaviour of the internuclear potential representing the interaction between two atoms (e.g. --CR), there are usually a certain number of closely spaced vibrational-rotational levels that approach dissociation. The properties of molecules in these highest levels are quite unusual (although often simply related to the long-range forces), and we shall refer to such molecules by a special classification: 'long-range molecules'. Restricting our attention to diatomic long-range molecules, we first review the general relationship between the potential energy curve and vibrational levels. The long-range portion of potential energy curves is examined in detail and the simple properties of vibrational levels sensitive to these long-range potentials discussed. Finally transitions (radiative, nonradiative, and collision-induced) are briefly described. [ABSTRACT FROM AUTHOR]

A reanalysis of several equilibrium properties of electron spin-polarized atomic nitrogen is presented, utilizing parameters from a new and improved theoretical calculation of the 7Σ+u state of molecular nitrogen which represents the interaction potential between two such spin-polarized atoms. The new potential well is significantly more shallow than previously assumed, resulting in substantial changes in the critical and triple point pressures and temperatures as calculated in the quantum theorem of corresponding states framework. The corresponding molar volumes are only slightly affected because the hard sphere radius is unchanged. Bulk samples are not expected to exhibit significant quantum behavior. Earlier conclusions on the relative stability of this material to single spin-flip processes remain unaltered. [ABSTRACT FROM AUTHOR]