engleski

Formation of ultracold lithium molecules via photoassociation

Diatomic heteronuclear 6Li7Li molecule belongs to the group of lithium isotopomer which member are also homonuclear 6Li2 i 7Li2 molecules. At small and intermediate interatomic distances all isotopomers have similar electronic energy potential curves. Differences in potentials curves of isotopomers are important in the long range region. Electronic states of 6Li7Li molecules which dissociated in the 2 2^S + 2 2^P asymptote are very important for ultra-cold molecules creation via photoassociation Schlöder at all. At large interatomic distances isotopic shift is larger than electrostatic interaction of atoms, electronic states of 6Li7Li molecules have characteristic of heteronuclear molecule with typical attractive van der Waals potential energy curves. At smaller interatomic distances, where electrostatic interaction is larger than isotopic shift, states of 6Li7Li molecule get characteristic of homonuclear molecule with the appropriate gerade-ungerade symmetry, and interaction potential have typical resonant behaviour Movre and Pichler. We have used ab-initio potential curves by Ratcliff at al. and asymptotic calculation by Marinecu and Dalgarno4 for homonuclear 7Li2 molecules, in order to construct energies and wavefunctions of few lowest electronic states of 6Li7Li molecule. Vibrational states of ground and excited electronic states of all isotopomers are analysed using Mapped Fourier Grid Hamiltonian method. We have calculated the probability of the photoassociation from the ground ultracold free state (s-wave) into the excited bound electronic states. Efficiency for cold molecules formation via photoassociation was compared for all isotopomers.

photoassociation; lithium; ultracold molecules

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