TRIPLET S-WAVE RESONANCE IN LI-6 COLLISIONS AND SCATTERING LENGTHS OFLI-6 AND LI-7

The triplet s-wave scattering length of Li-6 is determined using two-p hoton photoassociative spectroscopy of the diatomic a (3) Sigma(u)(+) State of Li-6(2). The measured binding energy of the highest-lying bou nd state, combined with knowledge of the potential, determines the s-w ave scattering length to be (-2160+/-250)a(0), where a(0) is the Bohr radius. This extraordinarily large scattering length signifies a near- threshold resonance. A complete table of singlet and tripler scatterin g lengths for collisions involving Li-6 and Li-7 determined from this and our previous spectroscopic investigations is given.