Pygmy dipole strength in 86Kr and systematics of N=50 isotones

The dipole strength of the N=50 nucleus 86Kr was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of energies of 7.9 and 11.2 MeV delivered by the linear accelerator ELBE and using quasi-monoenergetic gamma rays of 10 energies within the range from 4.7 to 9.3 MeV delivered by the HIgS facility. A high-pressure gas target was used. We identified 42 levels up to an excitation energy of 10.1 MeV. Simulations of gamma-ray cascades were performed to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. The photoabsorption cross section derived in this way up to the neutron-separation energy is combined with the photoabsorption cross section obtained from a recent (gamma,n) experiment at HIgS. The enhanced E1 strength found in the range from 6 to 10 MeV is compared with that in the N = 50 isotones 88Sr, 90Zr, and 92Mo and with predictions of calculations within the quasiparticle-phonon model.