An optical potential appropriate to elastic scattering of neutrons by oxygen is calculated with the starting point being the basic nucleon-nucleon interaction. A soft core force is employed so that matrix elements are finite and perturbation expansions are (apparently) convergent. All terms up to second order in the interaction are retained including correlation effects previously ignored. The calculations are carried out in a space large enough to minimize truncation effects. The resulting nonlocal energy dependent complex optical potential is used to calculate low energy $s$-wave phase shifts. These are compared with the results generated by an empirically fitted optical potential and with the results of previous calculations. The scattering length and effective range parameter are also calculated. Given the nature of the calculation, the results are quite encouraging.

NUCLEAR REACTIONS $n$-${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, optical potential, approximate many-body scattering theory.

• Received 29 August 1977

DOI:https://doi.org/10.1103/PhysRevC.18.632