  We study the spin-parity distribution P(J$^{\pi}$,E) of $^{156}$Gd excited
states above the neutron separation energy $S_{n}=8.536$ MeV
\cite{156Gd_list_of_levels} that are expected to be populated via the 1-step
neutron pickup reaction $^{157}$Gd($^{3}$He,$^{4}$He)$^{156}$Gd. In analogy
with the rotor plus particle model \cite{Bohr&Mottelson-II}, 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 \cite{Woods-Saxon:1954}
in $^{157}$Gd. The particle-core interaction usually dominated by a Coriolis
coupling are accounted via first order perturbation theory
\cite{VGGueorguiev:07062002}. The reaction cross section to each excited state
in $^{156}$Gd is calculated as coherent contribution using a standard reaction
code \cite{CHUCK} 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
\cite{VGGueorguiev:07062002}. 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 $\rightarrow$
$^{4}$He+$^{156}$Gd$^{\star}$ has a smooth formation probability P(J$^{\pi}$,E)
within the energy range relevant to the desired reaction $^{155}$Gd+n
$\rightarrow$ $^{156}$Gd$^{\star}$. The formation probability P(J$^{\pi}$,E)
resembles a Gaussian distribution with centroids and widths that differ for
positive and negative parity states.
