  We measure a zero crossing in the scattering length of a mixture of the two
lowest hyperfine states of 6-Li. To locate the zero crossing, we monitor the
decrease in temperature and atom number arising from evaporation in a CO2 laser
trap as a function of magnetic field B. The temperature decrease and atom loss
are minimized for B=528(4) G, consistent with no evaporation. We also present
preliminary calculations using potentials that have been constrained by the
measured zero crossing and locate a broad Feshbach resonance at approximately
860 G, in agreement with previous theoretical predictions. In addition, our
theoretical model predicts a second and much narrower Feshbach resonance near
550 G.
