Failure of Bohr's compound nucleus hypothesis for theMo98(n,γ)Mo99reaction

Some remarkable features in the radiative deexcitation of narrow resonant states formed by slow neutron capture in ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$ are pointed out. Earlier investigations indicating strong correlations between radiative widths and the single particle widths of both initial and final states involved in the reaction have been extended. A more precise set of resonance neutron widths has been developed from new total cross section measurements on isotopically separated molybdenum. From high resolution Ge(Li) detector measurements, a more complete set of $\gamma$-ray transition intensities was derived. The resulting intensities are compared with intensities calculated from the valence neutron transition model of Lynn, with dipole matrix elements calculated from the ABACUS code of Auerbach. We conclude that the valence model works surprisingly well for ground state transitions from resonances with reduced widths of larger than about ${10}^{-3\mathrm{}}$ single particle units. For smaller resonances, correlations persist, but these must be accounted for by other mechanisms.