**
**

#### Bulg. J. Phys. vol.44 no.4 (2017), pp. 489-497

#### Neutron Transfer Reactions for Deformed Nuclei Using Sturmian Basis States

V.G. Gueorguiev

go back^{1,2}, J.E. Escher^{3}^{1}*Ronin Institute, NJ, USA*^{2}*Institute for Advanced Physical Studies, Sofia, Bulgaria*^{3}*Lawrence Livermore National Laboratory, Livermore, California, USA*Abstract.We study the spin-parity distribution P(J^{π},E) of^{156}Gd excited states above the neutron separation energyS= 8.536 MeV [1] that are expected to be populated via the 1-step neutron pickup reaction_{n}^{157}Gd(^{3}He,^{4}He)^{156}Gd. In analogy with the rotor plus particle model [2], we view excited states in^{156}Gd as rotational excitations built on intrinsic states consisting of a neutron hole in the^{157}Gd core; that is, a neutron removal from a deformed Woods-Saxon type single-particle state [3] in^{157}Gd. The particle-core interaction usually dominated by a Coriolis coupling are accounted via first order perturbation theory [4]. The reaction cross section to each excited state in^{156}Gd is calculated as coherent contribution using a standard reaction code [5] based on spherical basis states. The spectroscopic factor associated with each state is the expansion coefficient of the deformed neutron state in a spherical Sturmian basis along with the spherical form factors [4]. The total cross section, as a function of the excitation energy, is generated using Lorentzian smearing distribution function. Our calculations show that, within the assumptions and computational modeling, the reaction^{3}He +^{157}Gd →^{4}He +^{156}Gd^{*}has a smooth formation probability P(J^{π},E) within the energy range relevant to the desired reaction^{155}Gd +n→^{156}Gd^{*}. The formation probability P(J^{π},E) resembles a Gaussian distribution with centroids and widths that differ for positive and negative parity states.

#### Full-text: PDF