Shell-Model Treatment of Nuclear Reactions

A method is developed for the calculation of resonant nuclear states which preserves as many features of the shell model as possible. It is an extension of the $R$-matrix theory. The necessary formulas are derived and a detailed description of the computational procedure is given. The method is valid up to the two-particle emission threshold. With the assumption of consecutive decay of the nucleus, the two-particle emission process can also be described. The treatment is antisymmetrized in all particles.