Prospects for Bose-Einstein Condensation in AtomicLi7andNa23

Abstract

We have determined the scattering length of the ground state ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ + ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ singlet potential from spectroscopic data on the highest $S=0\mathrm{}$ bound states. Combining this with a previously obtained triplet value we find the first example of an alkali atom hyperfine state (the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ $F=1\mathrm{}$, $M_F=-1\mathrm{}$ state) for which the scattering length is positive. This implies a stable Bose condensate in future attempts to realize Bose-Einstein condensation in a magnetically trapped ultracold gas sample. We also predict magnetic-field-dependent resonances in the collision between atoms in the hyperfine state studied.