The effect of coupling of the two-phonon states on elastic and $2^{+}$ inelastic cross sections is calculated for 8 MeV neutrons incident on ${}_{}{}^{76,80,82}{}_{}{}^{}\mathrm{Se}$. Isospin optical parameters and deformation parameters are determined from comparison with data. The values of $\beta$ are larger than one would expect on the basis of measured values from ($p$,$p^{\prime }$) and Coulomb excitation.

NUCLEAR REACTIONS ${}_{}{}^{76,80,82}{}_{}{}^{}\mathrm{Se}$ ($n$,$n$) and ($n$,$n^{\prime }$); cross sections calculated with coupled channels; effects of two-phonon coupling.

• Received 23 December 1980

DOI:https://doi.org/10.1103/PhysRevC.24.2359