Abstract
A Z-expansion method, in which the spin-orbit and electron-electron Coulomb interactions are treated by first-order perturbation theory, is developed for 3P10-1S0 intercombination-line transitions in helium-like ions. Reliable results are obtained for ions with nuclear charge Z<or=14. It is shown that the range of validity of non-relativistic calculations is substantially larger for dipole-allowed than for intercombination-line transitions.