Observation of low-lying resonances in the quasicontinuum of ^195,196Pt and enhanced astrophysical reaction rates

¹ Department of Physics, University of Oslo, N-0316 Oslo, Norway
² Department of Physics, University of Stellenbosch, 7602 Stellenbosch, South Africa
³ Air Force Technical Applications Center, Patrick Air Force Base, Florida, USA
⁴ Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
⁵ Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, Hungary

^a e-mail: francesca.giacoppo@fys.uio.no

Published online: 28 May 2015

Abstract

An excess of strength on the low-energy tail of the giant dipole resonance recently has been observed in the γ-decay from the quasicontinuum of ^195,196Pt. The nature of this phenomenon is not yet fully investigated. If this feature is present also in the γ-ray strength of the neutron-rich isotopes, it can affect the neutron-capture reactions involved in the formation of heavy-elements in stellar nucleosynthesis. The experimental level density and γ-ray strength function of ^195,196Pt are presented together with preliminary calculations of the corresponding neutron-capture cross sections.