[en] The high spin states in the N=80 odd-A ¹⁴¹Pm nucleus have been investigated by in-beam γ-spectroscopic techniques following the reaction ¹³³Cs(¹²C, 4n)¹⁴¹Pm at E=65 MeV using a modest γ detector array, consisting of seven Compton-suppressed high purity germanium detectors and a multiplicity ball of 14 bismuth germanate elements. Thirty new γ rays have been assigned to ¹⁴¹Pm on the basis of γ-ray singles and γγ-coincidence data. The level scheme of ¹⁴¹Pm has been extended upto an excitation energy of 5.2 MeV and spin ((35)/(2))ℎ and 16 new levels have been proposed. Spin-parity assignments for most of the newly proposed levels have been made on the basis of the deduced directional correlation orientation ratios for strong transitions. The meanlives of a few excited states have been determined from the pulsed beam-γγ coincidence data using the generalised centroid-shift method. The level structure is discussed in the light of known systematics of neighbouring N=80 isotonic nuclei

[en] Different multi quasiparticle excitations may also drive the nucleus to form different shapes and sometimes shape coexistence may be observed. Study of high spin states of ¹³⁷La provides us a good scope to study the role of multi quasiparticle excitations and their role in the phenomena of shape change

[en] The high spin states in odd-odd ¹⁴²Pm have been studied using the reaction ¹³³Cs(¹³C, 4n)¹⁴²Pm at E=63 MeV with a view to extend the level scheme, reported earlier by using α-induced reaction to higher spins

[en] In-beam measurements of nanosecond lifetimes have been undertaken for some of the excited states in near-spherical nuclei ^142,143Pm using the pulsed-beam γ coincidence technique and the generalized centroid-shift method of analysis. The ¹³³Cs(¹³C,xn) reaction with a 60 MeV pulsed beam of ¹³C was used to populate the excited states in the respective nuclei. The measured mean lifetimes have been compared with corresponding single-particle estimates

[en] Excited states of ¹³⁷Ce, populated in the ¹³⁰Te(¹²C,5n) reaction at a beam energy of 65 MeV, have been investigated by γγ coincidence spectroscopy using a modest Clover Ge array. Unique spin-parity assignments have been made for most of the levels at high spin and excitation energy by using DCO ratios and polarization information. The known level scheme of ¹³⁷Ce has been considerably revised on the basis of the new information. A sequence of M1 transitions, developed on the 5379.1-keV (33/2)(ℎ/2π) level has been suggested to be a positive-parity band through unambiguous assignment of multipolarity of 1124.1- and 836.1-keV γ rays. Another positive-parity bandlike structure has been seen, starting at the 2928.4-keV (19/2)⁺ level. Total Routhian surface calculations have been done to predict underlying multi-quasiparticle configurations for the observed bands

[en] The high spin states in the ¹³⁹Ce nucleus have been studied by in-beam γ-spectroscopic techniques using the reaction ¹³⁰Te(¹²C,3n)¹³⁹Ce at E_beam=65 MeV. A gamma detector array, consisting of five Compton-suppressed Clover detectors was used for coincidence measurements. 15 new levels have been proposed and 28 new γ transitions have been assigned to ¹³⁹Ce on the basis of γγ coincidence data. The level scheme of ¹³⁹Ce has been extended above the known 70 ns (19/2)^- isomer up to ∼6.1 MeV in excitation energy and (35/2)(ℎ/2π) in spin. The spin-parity assignments for most of the newly proposed levels have been made using the deduced Directional Correlation from Oriented states of nuclei (DCO ratio) and the Polarization Directional Correlation from Oriented states (PDCO ratio) for the de-exciting transitions. The observed level structure has been compared with a large basis shell model calculation and also with the predictions from cranked Nilsson-Strutinsky (CNS) calculations. A general consistency has been observed between these two different theoretical approaches.

[en] We have studied the high spin states in the N=80¹³⁷La nucleus by in-beam γ-spectroscopic techniques following the reaction ¹³⁰Te(¹¹B, 4n)¹³⁷La at E_beam=52 MeV using an array, consisting of 8 Compton-suppressed Clover germanium detectors. Forty five new γ rays have been assigned to ¹³⁷La on the basis of γ ray singles, γγ doubles and γγγ triples coincidence data. Thirty eight new levels have been proposed and the level scheme of ¹³⁷La has been extended above the known 360 ns 192^- isomer up to an excitation energy of ∼6 MeV and spin 392-bar . The spin-parity assignments for most of the newly proposed levels have been made using the deduced directional correlation orientation and polarisation information for the de-exciting transitions. The new scheme consists, among others, two decay sequences having states with alternating parity connected by E1 transitions. An attempt has been made to understand these interesting structure by a modest shell model calculation

[en] The high spin states in the N=79 odd-odd ¹³⁶La nucleus have been investigated by in-beam γ-spectroscopic techniques following the ¹³⁰Te(¹¹B,-bar 5n)¹³⁶La reaction at E=52 MeV using an array, consisting of eight Compton-suppressed clover germanium detectors. Thirty nine new γ rays have been assigned to ¹³⁶La on the basis of γ ray singles and γγ-coincidence data. The level scheme of ¹³⁶La has been extended above the known 115 ms isomer upto an excitation energy of 4.6 MeV and spin 18-bar . Thirty one new levels have been proposed and spin-parity assignments for most of the newly proposed levels have been made on the basis of the deduced asymmetry ratios and polarisation information for the de-exciting transitions. The observed positive parity yrast band has been compared with the theoretical calculation, done within the framework of particle rotor coupling model (PRM) where the two odd quasi-particles are coupled to an axially symmetric core. The level structure has been discussed in the light of the known systematics of the neighbouring N=79 isotonic nuclei