  Spin-orbit effects on electron-electron interaction are studied
theoretically. The corrections to the Coulomb interaction of quantum well
electrons induced by the spin-orbit coupling are derived. The developed theory
is applied to calculate the energy spectrum fine structure of an electron pair
triplet states localized in small lateral disk-shaped quantum dots. We show
that the spin degeneracy of a triplet state is completely lifted in anisotropic
quantum dots. Isotropic quantum dots also demonstrate peculiar fine structure
of triplet states caused by the spin-orbit interaction.
