On the sudden approximation as applied to (d, p) reactions
Results of the sudden approximation are compared to predictions of the conventional DWBA and to experiment. The asymptotic spectroscopic amplitude obtained by the sudden approximation is interpreted as the maximum limit of its true value. The main approximations of the model are asserted to stem from violations of the completeness of the virtual neutron wavefunctions and the crude application of the sudden approximation. It appears impossible to separate these two points. Improvements of the model are discussed.