  We studied spin-dependent two-body inelastic collisions in F=2 87Rb
Bose-Einstein condensates both experimentally and theoretically. The 87Rb
condensates were confined in an optical trap and selectively prepared in
various spin states in the F=2 manifold at a magnetic field of 3.0 G. Measured
atom loss rates are found to depend on spin states of colliding atoms. We
measured two fundamental loss coefficients for two-body inelastic collisions
with the total spin of 0 and 2; the coefficients determine loss rates for all
the spin pairs. The experimental results for mixtures of all the spin
combinations are in good agreement with numerical solutions of the
Gross-Pitaevskii equations that include the effect of a magnetic field
gradient.
