Description of radiative and weak strength functions of nuclear compound states within a semimicroscopic approach

A semi microscopic approach is formulated and applied for a number of nuclei to describe quantitatively photon and weak strength functions of nuclear compound states corresponding to neutron resonances (weak transitions imply the P-odd mixing of the compound states with opposite parity). The approach is based on the semi microscopic consideration of the low-energy tail of the corresponding giant resonances by means of both the continuum-RPA description of particle-hole states and phenomenological description of quasiparticle damping within the framework of an optical model. The temperature version of the approach is used to describe compound-to-compound transitions, whereas the transitions to the ground and low-lying states of nuclei are described with the use of the approach extended to the case of taking nucleon pairing into consideration. The single adjustable parameter determining the strength of the single-quasiparticle damping is found for each nucleus by the comparison of the calculated and experimental values of the mean total radiative width of neutron resonances. The calculation results, concerned with root-mean-squared matrix elements of the parity-violating nuclear mean field and the E 1 and M 1 strength functions corresponding to the gamma-decay of neutron resonances, are compared with experimental data