  We use a Hartree-Fock-Koopmans approach to study spin and interaction effects
in a diffusive or chaotic quantum dot. In particular, we derive the statistics
of the spacings between successive Coulomb-blockade peaks. We include
fluctuations of the matrix elements of the two-body screened interaction,
surface-charge potential, and confining potential to leading order in the
inverse Thouless conductance. The calculated peak-spacing distribution is
compared with experimental results.
