Low-lying dipole strength in Cr-52

The low-lying dipole strength in Cr-52 was measured in nuclear resonance fluorescence experiments using a quasimonochromatic, linearly polarized photon beam. The parities of the excited dipole states were determined by the intensity asymmetry of resonantly scattered gamma rays with respect to the polarization plane of the incident photon beam. We observed 62 resonances at excitation energies between 7.5 and 12.1 MeV. The observed M1 and E1 strengths were compared via random-phase-approximation calculations using the Skyrme interaction. The effects of two-particle-two-hole configuration mixing and tensor force on dipole strength distributions were investigated.