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High-spin excited states of $^{135}\mathrm{Pm}$ have been investigated using the $^{107}\mathrm{Ag}(^{32}\mathrm{S}$, $2p2n$) reaction at 145-MeV beam energy. Three negative-parity bands have been investigated up to $\ensuremath{\sim}9.0\ensuremath{-}$, $7.6\ensuremath{-}$, and $6.9\ensuremath{-}\mathrm{MeV}$ excitation energies with spin parities $(55/{2}^{\ensuremath{-}})$, $(49/{2}^{\ensuremath{-}})$, and $(47/{2}^{\ensuremath{-}})\phantom{\rule{4pt}{0ex}}\ensuremath{\hbar}$, respectively. The experimental results have been interpreted using the triaxial projected shell model. It is shown that the observation of the parallel band structures can be explained in terms of crossing of two $s$ bands with the yrast band, which is a rare phenomenon for an odd-$A$ nucleus. Further, the lifetimes of levels in yrast band have been extracted using Doppler shift attenuation method. The evaluated $B(E2)$ values of yrast states show the loss of collectivity at higher spin, attributed to the alignment process.

We report measurement of the $g$-factor for the ${11/2}^{\ensuremath{-}}$ isomeric state at 535 keV in $^{133}\mathrm{La}$, employing the time differential perturbed angular distribution technique (TDPAD). This isomer was populated in the reaction $^{126}\mathrm{Te}(^{11}\mathrm{B}$, $4n)^{133}\mathrm{La}$ at beam energy of 52 MeV. From the observed nuclear spin precession, analysed through combined, magnetic dipole and electric quadrupole hyperfine interactions, we obtain the $g$ factor for the $11/{2}^{\ensuremath{-}}$ state as $g=1.16\ifmmode\pm\else\textpm\fi{}0.07$. In addition, this analysis provides the spectroscopic quadrupole moment $|Q|=1.71\ifmmode\pm\else\textpm\fi{}0.34\phantom{\rule{3.33333pt}{0ex}}b$, yielding the deformation parameter $\ensuremath{\beta}=0.28\ifmmode\pm\else\textpm\fi{}0.10$. Further, we have performed theoretical calculations using the large-scale shell model and the Monte Carlo shell model. The results successfully describe the low-lying levels and the band structures of $^{133}\mathrm{La}$, and the calculated $g$ factor compares well with the values obtained from our experiment. The dominant configuration of $11/{2}^{\ensuremath{-}}$ isomeric state in $^{133}\mathrm{La}$ is inferred to be $\ensuremath{\pi}({h}_{11/2})\ensuremath{\bigotimes}^{132}\mathrm{Ba}({0}^{+})$.

The intermediate and high-spin states of the $^{134}\mathrm{Ba}$ nucleus have been investigated up to spin ${I}^{\ensuremath{\pi}}=({20}^{\ensuremath{-}})$ using the $^{124}\mathrm{Sn}(^{13}\mathrm{C}, 3n)^{134}\mathrm{Ba}$ reaction at a beam energy of 48 MeV. The ${R}_{\mathrm{DCO}}$ and polarization asymmetry measurements were carried out to assign the spin and parity of the levels. Three ($\mathrm{\ensuremath{\Delta}}I=2$) negative parity bands were studied above the 1985.9 keV level having spin ${I}^{\ensuremath{\pi}}={5}^{\ensuremath{-}}$. The two quasiparticle $\ensuremath{\nu}[{h}_{11/2}\ensuremath{\bigotimes}({s}_{1/2}/{d}_{3/2})]$ configuration has been assigned to these bands based on the systematics of the $\mathrm{Ba}$ (even-$N$) isotopes and similarity in the behavior of signature splitting and $B(M1)/B(E2)$ ratios. Further, two ($\mathrm{\ensuremath{\Delta}}I=1$) dipole bands have also been observed starting at the 5677.9 and 5284.5 keV levels with spin ${I}^{\ensuremath{\pi}}={14}^{\ensuremath{-}}$ and ${15}^{+}$, respectively. The configuration of these bands was suggested from the systematics of the similar structure in the neighboring nuclei. Tilted axis cranking (TAC) calculations were carried out using the four quasiparticle $\ensuremath{\pi}[{h}_{11/2}({g}_{7/2}/{d}_{5/2})]\ensuremath{\bigotimes}\ensuremath{\nu}{[{h}_{11/2}]}^{2}$ and $\ensuremath{\pi}[{h}_{11/2}({g}_{7/2}/{d}_{5/2})]\phantom{\rule{4pt}{0ex}}\ensuremath{\bigotimes}\phantom{\rule{4pt}{0ex}}\ensuremath{\nu}[{h}_{11/2}{d}_{3/2}]$ configurations for bands D1 and D2, respectively. The TAC calculations and systematic studies of similar structures in the neighboring $N=78$ isotones suggest that the dipole band (D1) observed at 5677.9 keV level may have the magnetic rotation character.

Lifetimes of excited states of the ground-state rotational band in the $^{136}\mathrm{Sm}$ nucleus have been measured up to ${I}^{\ensuremath{\pi}}={20}^{+}$ using the Doppler-shift attenuation method. The states were populated in the reaction $^{107}\mathrm{Ag}$($^{32}\mathrm{S}$, $1p2n$) at 145-MeV beam energy and the $\ensuremath{\gamma}$ rays emitted from the excited states were detected using the Indian National Gamma Array at the Tata Institute of Fundamental Research, Mumbai. The extracted transitional quadrupole moments indicate a reduction of collectivity with increasing spin after the band crossing. The results have been compared with the predictions of the cranked shell model as well as the triaxial projected shell-model calculations and indicate that the nucleus evolves from prolate $\ensuremath{\gamma}$-soft to a stable triaxially deformed shape after the first and the second crossing involving $\ensuremath{\pi}{h}_{11/2}^{2}$ and $\ensuremath{\pi}{h}_{11/2}^{2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}^{2}$ configurations, respectively.

High-spin states in Zr89 were populated in the Se80(C13,4n) reaction, and γ-ray coincidences were measured using the Indian National Gamma Array. The level scheme of Zr89 has been extended up to spin I=49/2 with the observation of a new dipole band. Directional correlation and polarization asymmetries of the γ rays have been measured to determine spin and parity of the levels. Line shapes of several transitions have been analyzed to determine lifetimes of the levels. Possible configurations of the band have been discussed using the cranked Nilsson-Strutinsky model. The calculations suggest a triaxial shape of the nucleus at high spins, and the band may represent rotation of the nucleus about the longest axis.

Evaporated α-spectra have been measured in coincidence with low energy discrete γ-rays from residual nucleus 68Zn populated by αn evaporation from compound nucleus 73Ge produced in the reaction 64Ni(9Be,αn)68Zn at E ( 9 Be) = 30 MeV. Low energy γ-gated α-particle spectra, for the first time, have been used to extract the nuclear level density (NLD) for the intermediate 69Zn nucleus in the excitation energy range of E ≈ 4-20 MeV. The slope of present NLD data as a function of excitation energy for 69Zn matches nicely with the slope determined from RIPL estimates for NLD at low energies and the NLD from neutron resonance data at neutron separation energy S n . The extracted inverse NLD parameter (k = A/ a ˜ ) has been used to determine the nuclear level density parameter value a at neutron separation energy S n for 69Zn. The cross section of 68Zn(n,γ) capture reaction as a function of neutron energy is then estimated employing the derived a ( S n ) in the reaction code TALYS. It is found that the estimated neutron capture cross section agrees well with the available experimental data without any normalization. The present result indicates that experimentally derived nuclear level density parameter can constrain the statistical model description of astrophysical capture cross section and optimize the uncertainties associated with astrophysical reaction rate.

Excited states of the $^{61}\mathrm{Ni}$ ($Z=28,N=33$) nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton suppressed germanium (clover) detectors as detection system for the emitted $\ensuremath{\gamma}$ rays. Seventeen new transitions have been identified and placement of six transitions have been modified with respect to the previous measurements, following which the level scheme of the nucleus has been extended up to an excitation energy ${E}_{x}\ensuremath{\approx}7$ MeV and spin $\ensuremath{\approx}10\ensuremath{\hbar}$. Higher excitations involving the ${g}_{9/2}$ orbital in the $fpg$ model space have been established. The experimental results on the level structure of the nucleus have been interpreted in the light of large basis shell model calculations that lead to an understanding of the single particle configurations underlying the level structure of the nucleus. The comparison can be suggestive of further refinements in the shell model interactions for better overlap of the theoretical results with the experimental data.

Excited states of the $^{64}\mathrm{Cu}\phantom{\rule{4pt}{0ex}}(Z=29,N=35)$ nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton-suppressed Clovers as detection system for the emitted $\ensuremath{\gamma}$ rays. More than 50 new transitions have been identified and the level scheme of the nucleus has been established up to an excitation energy ${E}_{x}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}\phantom{\rule{4pt}{0ex}}6$ MeV and spin $\ensuremath{\sim}10\ensuremath{\hbar}$. The experimental results have been compared with those from large-basis shell-model calculations that facilitated an understanding of the single-particle configurations underlying the level structure of the nucleus.

The high-spin states in $^{133}\mathrm{Cs}$, populated using the reaction $^{130}\mathrm{Te}(^{7}\mathrm{Li},4n)$ with 45-MeV beam energy, have been extended up to an excitation energy of 5.265 MeV using the Indian National Gamma Array. The observed one- and three-quasiparticle bands in $^{133}\mathrm{Cs}$, built on the $\ensuremath{\pi}{h}_{11/2},\phantom{\rule{0.28em}{0ex}}\ensuremath{\pi}{g}_{7/2}$, $\ensuremath{\pi}{d}_{5/2}$; and ${(\ensuremath{\pi}{g}_{7/2}\ensuremath{\pi}{d}_{5/2})}^{1}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}^{\ensuremath{-}2}$ configurations, respectively, have similar structure as seen in the lighter odd-$A$ Cs isotopes. The experimental level scheme has been compared with the large-scale shell model calculation without truncation using the $jj55pna$ interaction, showing a good agreement for both positive- and negative-parity states.