Two-phonon 1{sup -} state in {sup 112}Sn observed in resonant photon scattering

Results of a photon scattering experiment on {sup 112}Sn using bremsstrahlung with an endpoint energy of E{sub 0}=3.8 MeV are reported. A J=1 state at E{sub x}=3434(1) keV has been excited. Its decay width into the ground state amounts to {gamma}{sub 0}=151(17) meV, making it a candidate for a [2{sup +}x3{sup -}]1{sup -} two-phonon state. The results for {sup 112}Sn are compared with quasiparticle-phonon model calculations as well as the systematics of the lowest lying 1{sup -} states established in other even-mass tin isotopes. In contrast to findings in the heavier stable even-mass Sn isotopes, no 2{sup +} states between 2 and 3.5 MeV excitation energy have been detected in the present experiment.