Energy--level splitting in antiprotonic helium atoms

Recent experiments on the laser-induced resonant annihilation provide a precise measurement of transition energies of antiprotonic helium atoms. Relativistic corrections of an order of $\alpha ^2$ to the pure Coulomb interaction will be taken into account in the theoretical description of energy spectra of antiprotonic helium atoms. The splitting of energy levels arising due to the spin-dependent part of the relativistic interaction is considered for a number of states of $^{3,4}\! H\! e\bar pe$ systems.