  The viscosity and thermal conductivity of binary, ternary and quaternary
mixtures of helium, neon, argon, and krypton at low density are computed for
wide ranges of temperature and molar fractions, applying the Chapman-Enskog
method. Ab initio interatomic potentials are employed in order to calculate the
omega-integrals. The relative numerical errors of the viscosity and thermal
conductivity do not exceed 1.e-6 and 1.e-5, respectively. The relative
uncertainty related to the interatomic potential is about 0.1%. A comparison of
the present data with results reported in other papers available in the
literature shows a significant improvement of accuracy of the transport
coefficients considered here.
