The heteronuclear alkali dimers have been proposed as candidates for quantum computing, high-precision measurements of fundamental constants, and studies of chemical reactions at ultracold temperatures. We calculate the potential energy curves, permanent dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear dimers XY (X, Y = Li, Na, K, Rb, Cs) using the coupled cluster with singles, doubles and triples (CCSDT) method. All electron quadruple-? basis sets are used for Li and Na, and small-core relativistic effective core potentials with quadruple-? quality basis sets are used for K, Rb and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. The dissociation energies are overestimated by only 14 cm-1 for LiNa and by no more than 114 cm-1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm-1, and the discrepancies for the anharmonic correction are less than 0.1 cm-1. To obtain the vibrational energies and wave functions the Schr�dinger equation for nuclei is solved with the B-spline basis set method. The transition dipole moments between all vibrational states and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation.

Vibrational state lifetimes of heteronuclear alkali dimers

248th National Meeting (2014)

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