[en] This thesis consists of two separate studies which are divided into Parts I and II. Part I includes the structural studies of /sup 118, 114/Cd nuclei. Earlier studies of stable /sup 112, 114/Cd nuclei showed some large deviations from the expected vibrational structure by the presence of extra 0⁺ and 2⁺ states at ≅1.2 MeV. The /sup 118,120/Cd nuclei were studied from the β decay of Ag produced in fission of ²³⁵U at the on-line isotope separator, TRISTAN, by γ-γ and β-γ coincidence, γ-multiscaling, and β singles endpoint measurements. The results show that the bandhead of the intruding configuration did indeed rise in excitation energy compared to the lighter Cd nuclei, whereas the vibrational states remained relatively constant. Furthermore, these studies led to the identification of a set of five closely-spaced states in ¹¹⁸Cd. This represents the first observation of all five members of the three-phonon multiplets. This fact qualifies ¹¹⁸Cd as the best example to data of a U(5) nucleus. Part II consists of a brief summary of the results obtained in comparative studies of certain aspects of the IBA and geometrical models. Aspects, such as, the effect of finite boson number of γ → g transitions in deformed nuclei, determination of finite boson numbers, and the effective γ values which can be derived from the IBA

[en] Angular correlation studies of ¹¹⁸¹²⁰Cd at TRISTAN have allowed the discovery and identification in each nucleus of two new 0⁺ states and their respective E2 decay properties. The results have been interpreted in terms of a simple schematic model based on the mixing of normal vibration-like and intruder rotation-like 2p-4h configurations

[en] The structure of the very neutron-rich Cd isotopes ^116,118,120Cd is studied in the interacting boson model. It has been found that both a U(5) (anharmonic vibration) and a non-U(5) Hamiltonian can describe both the low-lying and the high-spin states of these nuclei well. Present experimental data on E2 transitions favour the non-U(5) Hamiltonian slightly. (author)

[en] At the KVI in Groningen, NL, several α-γ coincidence experiments were performed. In these experiments the decay of the excited nucleus can be studied in great detail, using HPGe detectors for high resolution gamma spectroscopy. At excitation energies above the neutron separation threshold in the region of isoscalar giant resonances the degree of population of excited states in the daughter nucleus after particle emission can be studied as a function of the excitation energy. Preliminary results from the analysis of the experiments on ¹²⁴Sn and ¹⁴⁰Ce are presented and discussed. A strong dependance of the population of excited states on the excitation energy is observed.

[en] By use of a pulsed tunable dye laser the isotope shift of the radioactive Cd-isotopes (¹⁰²Cd <= A <= ¹²⁰Cd) in the 5s²¹S₀ - 5s 5p ³P₁ lambda = 326 nm line has been measured at the on-line mass separator ISOLDE/CERN. (orig.)

[en] The spectroscopic studies of fission fragments provide direct information on the nuclear excited states, which is related to the shape and structure of the fragment nuclei. With the advent of large gamma array, it is now possible to identify the individual fission fragments by employing the γ-- γ coincidence technique. We have carried out an experiment at 15UD IUAC Pelletron facility, New Delhi, to study the ²³⁸U(¹⁸O,f) reaction at 100 MeV, using Indian National Gamma Array (INGA), comprising of 18 clover germanium detectors. The data was collected in an event-by-event mode with the minimum requirement of three-fold prompt γ-ray coincidence. The Eγ-Eγ coincidence matrix was constructed from the prompt γ-ray coincidence data analyzed using RADWARE software and we could identify a given fragment from the background of hundreds other nuclei which are produced simultaneously in the fission process. For many of the nuclei, we could observe the gamma ray transitions having spins of up to 14⁺

[en] The /sup 118,120/Cd nuclei were studied from the decay of Ag produced from the fission of /sup 235/U. The resulting systematics of the cadmium nuclei show that the intruding configuration bandheads have in fact risen in excitation energy relative to those observed in /sup 112,114/Cd and are well-separated from the two-phonon triplet of states. These results also led to the identification of a set of five states, in /sup 118/Cd whose close-spacing in excitation energy and decay transition probabilities seem to qualify /sup 118/Cd as the first example of a U(5) nucleus

[en] The mass excess of the neutron-rich nucleus ¹²²Cd is measured by transfer reactions ¹²²Sn(¹⁸O, ²⁰Ne)¹²⁰Cd and ¹²⁴Sn(¹⁸O, ²⁰Ne)¹²²Cd. Its value is derived to be -80.73 +- 0.04 MeV. In addition, a few new levels of ¹²'0^,122Cd are observed

[en] New high-spin levels have been identified in the nucleus ¹²⁰Pd from analysis of the coincidence gamma rays observed in the ²³⁸U(α, f_γγγ) reaction. Recoiling fragments were detected with the Rochester heavy-ion detector array, CHICO, in coincidence with gamma-rays using Gammasphere. An A=110-130 mass-gated γ-γ-γ cube from this experiment was constructed and analyzed for coincident gamma-rays in several nuclei near A=120. New results for neutron-rich ¹¹⁸Pd and ¹²⁰Pd have been obtained. The ¹²⁰Pd level scheme was extended to spin of 10⁺ by building on the new low-energy gamma rays identified in decay studies of ¹²⁰Rh. The details of the ¹¹⁸Pd level scheme derived from this work are compared to previous work. The systematics of the yrast levels in even-even Pd and Cd isotopes are presented and the symmetry of energy levels around N 68 is discussed. A new 10⁺ level in ¹²⁴Cd has been observed. The population intensity of even-even neutron-rich Cd isotopes is deduced, indicating that nuclides near ¹²⁰Cd are preferentially populated following alpha-induced fission of ²³⁸U

[en] It has been shown that there are significant deviations from the expected U(5) dynamical symmetry for ^{110,112,114,116}Cd. However, there is very significant mixing with intruder states in this region. In this paper, we investigated states in the heavier ^120,124,126Cd populated via beta decay. These nuclei exhibit similar patterns to the lighter Cd isotopes even though the intruder states are much higher in energy.