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The adiabatic potential energy curves and the spectroscopic constants of the ground and the first excited states of LiK+, LiRb+ and LiCs+ ionic molecules have been performed. The transition dipole moment between the ground (X2Σ+) and the first excited (22Σ+) state have been determined for each ionic molecule. We have used an ab initio approach involving non-empirical pseudo-potentials with core valence effects taken into account through parameterized l-dependent polarization potentials. Our spectroscopic constants of the ground and the first excited states are in good agreement with the available theoretical works. The potential energy curves and the transition dipole moment are used to estimate the radiative lifetimes of the vibrational levels of the 22Σ+ state for the first time. In addition to the bound-bound contribution, the bound-free term has been evaluated exactly and using the Franck-Condon (FC) approximation and added to the total radiative lifetime. These data can help experimentalists to optimize photoassociative formation of ultracold molecules and their longevity in a trap or in an optical lattice. [ABSTRACT FROM AUTHOR]

Theory and experiment are being used together to explore spectra from sodium and xenon gas mixtures similar to those used in high pressure lamps. Results from high precision measurements of the absorption coefficients over the wavelength range from 425 to 760 nm are presented with 0.02 nm spectral resolution. Measurements of the sodium density with ±5 percent uncertainty complement the absorption coefficient measurements. The experimental data are compared to quantum-mechanical spectral calculations that utilize recent cold collision and other data. The spectra are sensitive to the interatomic potentials, especially in the far wings in which molecular features such as vibrational-rotational and satellite structures are exhibited. The particular results for Na-Xe are analyzed in detail. [ABSTRACT FROM AUTHOR]