COUPLED-CHANNEL APPROACH FOR PIONIC ATOMS H-1 AND HE-3

The momentum-space method by Vincent and Phatak is extended to deal wi th a two-particle bound state, coupled to other open channels. The pre sent approach is applied to two systems of coupled channels represente d by pi(-)p, pi(0)n, gamma n and pi(-3)He, pi(03)H, gamma(3)H, respect ively. The energy shifts and absorption widths of the Is revels of pio nic hydrogen and the He-3 pi-atom are calculated and compared with exi sting experimental data.