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New transitions in neutron-rich Y100 have been identified in a Be9+U238 experiment with mass and Z gates to provide full fragment identification. These transitions and high spin levels of Y100 have been investigated by analyzing the high statistics γ-γ-γ and γ-γ-γ-γ coincidence data from the spontaneous fission of Cf252 at the Gammasphere detector array. Two new bands, 14 new levels, and 23 new transitions have been identified. The Kπ=4+ new band decaying to a 1s isomeric state is assigned to be the high-K Gallagher-Moszkowski (GM) partner of the known Kπ=1+ band, with the π5/2[522] - ν3/2[411] configuration. This 4+ band is also proposed to be the pseudospin partner of the new Kπ=5+ band with a 5+π5/2[422] - ν5/2[413] configuration, to form a π5/2[422] - ν[3125/2,3/2] neutron pseudospin doublet. Constrained triaxial covariant density-functional theory and quantal particle rotor model calculations have been applied to interpret the band structure and available electromagnetic transition probabilities and are found to be in good agreement with experimental values.

The low-lying non-yrast states in $^{114}\mathrm{Te}$ have been investigated using the Indian National Gamma Array through the fusion-evaporation reaction $^{112}\mathrm{Sn}(^{4}\mathrm{He},2n)$ at a beam energy of 37 MeV. Eight new $\ensuremath{\gamma}$ transitions have been placed in the level scheme to establish the quasi-$\ensuremath{\gamma}$ band in this nucleus. Spin and parity of several excited states have been assigned from the present spectroscopy measurements. The comparison of experimental results on the observed bands with the interacting boson model (IBM) and triaxial projected shell model (TPSM) confirms the existence of the quasi-$\ensuremath{\gamma}$ band structure in the $^{114}\mathrm{Te}$ nucleus.

The excited states in the transitional nucleus $^{131}\mathrm{Xe}$ have been populated by using $\ensuremath{\alpha}$-induced fusion-evaporation reaction and the de-exciting $\ensuremath{\gamma}$ rays were detected with the Compton suppressed clover detector setup of the Indian National Gamma Array coupled to digital data acquisition system. The existing level structure of $^{131}\mathrm{Xe}$ has been significantly extended with the observation and placement of 72 new $\ensuremath{\gamma}$-ray transitions. The use of light-ion ($\ensuremath{\alpha}$) beam helped to identify several new band structures in $^{131}\mathrm{Xe}$ with different quasiparticle (qp) configurations. The multipolarities of the observed $\ensuremath{\gamma}$ rays have been determined on the basis of the directional correlation from oriented states ratio and polarization asymmetry measurements. The yrast negative-parity band has been confirmed up to ${35/2}^{\ensuremath{-}}$ spin and the highly nonyrast signature partner of this band has been identified for the first time. The positive-parity band, based on the ${3/2}^{+}$ ground state, has been extended up to ${23/2}^{+}$ with the observation of a signature inversion, which signifies a pair of particle alignment around the spin of 15/2 $\ensuremath{\hbar}$. A dipole band, consisting of $M1$ transitions has been identified and assigned a 5-qp configuration. A new band structure built on a 3-qp ${23/2}^{+}$ state has been observed with a large signature splitting. A comparison in the isotopic and isotonic chains reveals the transitional nature of the $N=77$ nuclei. Total Routhian surface calculations have been performed to understand the structure of $^{131}\mathrm{Xe}$ associated with different configurations.

Rotational band structures and low-lying single-particle levels in $^{117}\mathrm{Sb}$ have been populated using reaction $^{115}\mathrm{In}(\ensuremath{\alpha}$, $2n)^{117}\mathrm{Sb}$ at a beam energy of 28 MeV and investigated using $\ensuremath{\gamma}$-ray spectroscopic techniques. The existing level scheme has been extended with the observation of 31 new transitions. The signature partner of the band structure based on the configuration of $\ensuremath{\pi}{g}_{7/2}\phantom{\rule{4pt}{0ex}}\ensuremath{\bigotimes}\phantom{\rule{4pt}{0ex}}2\mathrm{p}\text{\ensuremath{-}}2\mathrm{h}$ of the $^{116}\mathrm{Sn}$ core has been established in $^{117}\mathrm{Sb}$ for the first time. Several single-particle nonyrast transitions connecting to various band structures have also been identified. Measurements of the DCO ratios, polarization asymmetry and angular distribution of the observed $\ensuremath{\gamma}$ rays have been carried out to assign the spin-parities to the levels of all the band structures and the low-lying single-particle states, populated in the present work. The spin-parities are also determined for the states of the two previously unassigned bands. The lower-spin structures have been interpreted on the basis of large-scale shell-model calculations using OXBASH. Particle Rotor Model (PRM) calculations have been carried out to explain the large signature splitting of the observed signature partner bands.

Background: Levels fulfilling the seniority scheme and relevant isomers are commonly observed features in semimagic nuclei; for example, in Sn isotopes (Z=50). Seniority isomers in Sn, with dominantly pure neutron configurations, directly probe the underlying neutron-neutron (νν) interaction. Furthermore, an addition of a valence proton particle or hole, through neutron-proton (νπ) interaction, affects the neutron seniority as well as the angular momentum. Purpose: Benchmark the reproducibility of the experimental observables, like the excitation energies (EX) and the reduced electric-quadrupole transition probabilities [B(E2)], with the results obtained from shell-model interactions for neutron-rich Sn and Sb isotopes with N

The excited states of $^{197}\mathrm{Tl}$ have been studied via $^{197}\mathrm{Au}(^{4}\mathrm{He}$, $4\mathrm{n})^{197}\mathrm{Tl}$ reaction at a beam energy of 50 MeV from the K-130 cyclotron at the Variable Energy Cyclotron Centre (VECC). The $\ensuremath{\gamma}$ rays were detected using the VECC array for Nuclear Spectroscopy (VENUS) with six Compton-suppressed clover HPGe detectors. An improved level scheme of $^{197}\mathrm{Tl}$ has been proposed from this work, which has been extended to 5.1 MeV of excitation energy and 39/2 $\ensuremath{\hbar}$ of spin from the placement of 28 new $\ensuremath{\gamma}$-ray transitions. Band crossings in the known one- and three-quasiparticle (qp) bands have been identified for the first time in this work. Two new bands, based on 3-qp and 5-qp configurations, have been observed for the first time in this nucleus; both of which are identified as the magnetic rotational (MR) in nature. The excitation energies of these bands are similar to that of the doubly degenerate bands observed for the similar 3-qp and 5-qp configurations in $^{195}\mathrm{Tl}$. These indicate a transition from an aplanar geometry of the neutron, proton, and the core angular momentum vectors to a planar one for neutron number $N\ensuremath{\ge}116$ in Tl isotopes. The total Routhian surface calculations suggest a change in shape from oblate for the 1-qp configuration to a near-spherical one for the 3- and 5-qp configurations. This is consistent with the observed MR nature of the bands with multi-qp configuration. The MR bands are well reproduced by a model calculations in the frame work of the shears mechanism with the principal axis cranking.

High spin band structures of neutron-rich $^{152--158}\mathrm{Pm}$ isotopes have been obtained from the measurement of prompt $\ensuremath{\gamma}$ rays of isotopically identified fragments produced in fission of $^{238}\mathrm{U}+^{9}\mathrm{Be}$ and detected using the VAMOS++ magnetic spectrometer and EXOGAM segmented Clover array at GANIL and also from the high statistics $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ and $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ data from the spontaneous fission of $^{252}\mathrm{Cf}$ using Gammasphere. The excited states in $^{157}\mathrm{Pm}$ and those above the isomers in even-$A$ Pm isotopes $^{152,154,156,158}\mathrm{Pm}$ have been identified for the first time. The spectroscopic information on the rotational band structures in odd-$A$ Pm isotopes has been extended considerably to higher spins and the possibility of the presence of reflection asymmetric shapes is explored. The configuration assignments are based on the results of cranked relativistic Hartree-Bogoliubov calculations. From the systematics of bands in odd-$A$ Pm isotopes and weak population of opposite parity bands, octupole deformed shapes in neutron-rich Pm isotopes beyond $N=90$ seem unlikely to be present.

The present Rapid Communication reports conclusive evidence for an antimagnetic rotational band in the odd-odd $^{142}\mathrm{Eu}$ nucleus. The parity of the states of a quadrupole sequence in this nucleus is identified firmly from polarization measurements using the Indian National Gamma Array, and lifetimes of some of the states in the same structure are measured using the Doppler-shift attenuation method. The decreasing trends of the deduced quadrupole transition strength $B(E2)$ with spin in the sequence along with the increasing ${J}^{(2)}/B(E2)$ values conclusively establish the origin of these states as arising from antimagnetic rotation. The results are well reproduced by numerical calculations within the framework of a semiclassical geometric model.

The high spin excited states of $^{169}\mathrm{Tm}$ have been studied via the $^{169}\mathrm{Tm}$($^{32}\mathrm{S}$, $^{32}\mathrm{S}^{\ensuremath{'}}$)$^{169}{\mathrm{Tm}}^{*}$ reaction at a beam energy of 164 MeV. The $\ensuremath{\gamma}$ rays were detected using an array of 19 Compton-suppressed clover HPGe detectors. The band based on the $[411]1/{2}^{+}$ Nilsson orbital has been extended to observe the band crossing for the first time in this nucleus. A sharp backbending, similar to $^{165}\mathrm{Tm}$, is observed in this nucleus which is in complete contrast with its immediate neighbor $^{167}\mathrm{Tm}$. The data were interpreted in the cranked shell model approach by calculating the total Routhian surfaces, crossing frequencies, and the interaction strengths for these nuclei which are in excellent agreement with the experimental data. It is suggested that the $N=98$ deformed shell gap has larger effect in determining the nature of alignment than its shape driving effect.

High-spin band structures of $^{200}\mathrm{Tl}$ have been studied by $\ensuremath{\gamma}$-ray spectroscopic methods using the $^{198}\mathrm{Pt}(^{7}\mathrm{Li},5n)^{200}\mathrm{Tl}$ reaction at 45 MeV of beam energy. The level scheme of $^{200}\mathrm{Tl}$ has been extended significantly and several new band structures have been established with the observation of 60 new transitions. The $\ensuremath{\pi}{h}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}{i}_{13/2}$ oblate band has been extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-odd Tl isotopes. Total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus. These calculations could reproduce the particle alignment frequency and suggest that the neutron pair alignment in $\ensuremath{\nu}{i}_{13/2}$ orbital induces $\ensuremath{\gamma}$ softness in $^{200}\mathrm{Tl}$.

Excitation functions were measured by stacked-foil activation technique for the $^{150}$Nd(p, xpyn) reaction using 97.65$%$ enriched $^{150}$Nd target. Measurement up to $\sim$50$%$ above barrier and down to 18$%$ below the barrier was performed using proton beam energy (E$_p$) of 7 - 15 MeV from VECC Cyclotron. The yield of suitable $\gamma$ rays emitted following the decay of relevant evaporation residues was determined using a 50$%$ High Purity Germanium (HPGe) detector.(p,n) cross section was found to follow the expected trend with a maximum value of 63.7(4.9)mb at E$_p$ $\sim$ 8.6 MeV. (p,2n) cross section gradually increased with E$_p$ and had maximum contribution to the total reaction cross section after E$_p$ $\sim$ 9.0 MeV. (p, p$^{\prime}$n) reaction channel also showed a reasonable yield with a threshold of E$_p$ $\sim$ 12.0 MeV. The experimental data were corroborated with statistical model calculations using different codes, viz., CASCADE, ALICE/91 and EMPIRE3.1. All the calculations using a suitable set of global parameters could reproduce the excitation function fairly well in the present energy range.

Fusion and quasi-elastic scattering measurements have been carried out for $^{6,7}\mathrm{Li}$+$^{197}\mathrm{Au}$ systems in the energy range $E/{V}_{b}\ensuremath{\sim}0.7$ to 1.5. Coupled-channel calculations including coupling to inelastic states of the target and projectiles are able to explain an enhancement in measured fusion cross sections at energies below the barrier. At energies above the barrier the complete fusion cross sections are found to be suppressed compared to the coupled-channel predictions for both systems. A systematic comparison of fusion cross sections of the weakly bound stable nuclei $^{6,7}\mathrm{Li}$ and halo nuclei $^{6,8}\mathrm{He}$ on a $^{197}\mathrm{Au}$ target is presented. Barrier distributions from quasi-elastic scattering are seen to shift towards higher energies with respect to fusion after inclusion of the breakup-$\ensuremath{\alpha}$ channel for both $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$.

High spin states of 142 Sm have been investigated using the fusion-evaporation reaction 116 Cd ( 31 P, p4n )a t beam energy 148 MeV using the Indian National Gamma Array (INGA). Approximately sixty new gamma transitions have been placed in the proposed level scheme, which has been extended up to ≈12.5 MeV. Several band-like structures including one dipole band and three quadrupole bands have been observed in the proposed level scheme. Lifetimes of several levels in the dipole band and quadrupole bands have been measured using doppler shift attenuation method (DSAM). The deduced B(M1) values for the dipole band have been compared with the semiclassical shears mechanism with the principle axis cranking (SPAC) model, and the dipole band has been interpreted as a magnetic rotational band. Comparisons between the experimental characteristics and cranked Nilsson-Strutinsky (CNS) calculations for the observed quadrupole bands indicate that these bands have been formed on the triaxial deformed shape of 142 Sm.

The high spin structure of ${}^{201}$Tl has been studied by $\ensuremath{\gamma}$-ray spectroscopic method using the ${}^{198}$Pt(${}^{7}$Li,4$n$)${}^{201}$Tl reaction at 45 MeV beam energy. The level scheme of ${}^{201}$Tl has been considerably extended through the observation of 31 new transitions. Several new band structures have been established. The 9/2${}^{\ensuremath{-}}$ oblate band has been significantly extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-$A$ Tl isotopes and with the even-even core nucleus ${}^{200}$Hg. The total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus.

Electron capture (EC) decay of ${}^{146}$Gd (${t}_{\frac{1}{2}}=48$ d) to the low lying states of ${}^{146}$Eu has been studied using high-resolution $\ensuremath{\gamma}$-ray spectroscopy. The ${}^{146}$Gd activity was produced by ($\ensuremath{\alpha},2n$) reaction at ${E}_{\ensuremath{\alpha}}=32$ MeV using a 93.8$%$ enriched ${}^{144}$Sm target. The level structure has been considerably modified from the measurement of $\ensuremath{\gamma}$-ray singles, $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidences and decay half lives. Lifetime measurement has been performed for the 3${}^{\ensuremath{-}}$ (114.06 keV) and 2${}^{\ensuremath{-}}$ (229.4 keV) levels of ${}^{146}$Eu using the mirror symmetric centroid difference (MSCD) method with LaBr${}_{3}$ (Ce) detectors. The lifetimes for these two states have been found to be 5.38 $\ifmmode\pm\else\textpm\fi{}$ 2.36 ps and 8.38 $\ifmmode\pm\else\textpm\fi{}$ 2.19 ps respectively. Shell model calculation has been performed using oxbash code in order to interpret the results.

The inclusive energy distributions of the complex fragments (3{

Low-spin structures in Mo-86,Mo-88 were populated using the Ni-58(Ar-36, x alpha yp) heavy-ion fusion-evaporation reaction at a beam energy of 111 MeV. Charged particles and gamma rays were emitted ...

The inclusive energy distributions of fragments with Z $\ensuremath{\ge}$ 3 emitted from the bombardment of $^{12}\mathrm{C}$ by $^{20}\mathrm{Ne}$ beams with incident energies between 145 and 200 MeV have been measured in the angular range ${\ensuremath{\theta}}_{\mathrm{lab}}~{10}^{\ifmmode^\circ\else\textdegree\fi{}}\text{\ensuremath{-}}{50}^{\ifmmode^\circ\else\textdegree\fi{}}$. Damped fragment yields in all cases have been found to be characteristic of emission from fully energy equilibrated composites; for B and C fragments, average Q values, $\ensuremath{\langle}Q\ensuremath{\rangle}$, were independent of the center-of-mass emission angle (${\ensuremath{\theta}}_{\mathrm{c.m}.}$), and the angular distributions followed a $~1/\mathrm{sin}{\ensuremath{\theta}}_{\mathrm{c.m}.}$-like variation, signifying long lifetimes of the emitting dinuclear systems. Estimates of total yields of these fragments have been found to be much larger than those predicted by the standard statistical model. This may be indicative of the survival of an orbiting-like process in the $^{12}\mathrm{C}+^{20}\mathrm{Ne}$ system at these energies.