Shell Model

The SU(3) irreducible representations (irreps) are characterised by the (lambda, mu) Elliott quantum numbers, which are necessary for the extraction of the nuclear deformation, the energy spectrum and the transition probabilities. These irreps can be calculated through a code which requires high computational power. In the following text a hand-writing method is presented for the calculation of the highest weight (h.w.) irreps, using two different sets of magic numbers, namely proxy-SU(3) and three-dimensional isotropic harmonic oscillator.

Polarized Raman spectra of nonsuperconducting SrFe 2 As 2 and superconducting K 0.4 Sr 0.6 Fe 2 As 2 ͑T c =37 K͒ microcrystals are reported. All four-phonon modes ͑A 1g + B 1g +2E g ͒ allowed by symmetry are found and identified. Shell model gives reasonable description of the spectra. No detectable anomalies are observed near the tetragonal-to-orthorhombic transition in SrFe 2 As 2 or the superconducting transition in K 0.4 Sr 0.6 Fe 2 As 2 .

The Global Positioning System, which was commonly known by the North American implementation called GPS; the GPS fails to provide an accurate Position, Navigation, and Time (PNT) signal over the Indian region. The positional accuracy of GPS is not up to the mark over the Indian region because the India is located near the equator. Moreover, the equatorial ionospheric grid point (IGP) of India differs from the ionospheric grid point of North America so in order to improve the positional accuracy of GPS over Indian region, the Indian Space Research Organization along with the Airport Authority of India has launched the space based augmentation satellite called GPS aided and Geo Augmented Navigation satellite (GAGAN) with PRN number 127 and 128. The GAGAN will make corrections in the ionospheric, ephemeris, and satellite clock errors in the navigation messages received from the GPS satellites; the certification of GAGAN is under progress. The objective of this research is to analyze th...

Shell model studies have been done for very neutron -rich nuclei in the range 50≤Z≤55 and 82≤N≤87. Good agreement of the theoretical level spectra with the experimental one for N=82, 83 I and Te nuclei is shown. Then the results for three very neutron-rich nuclei 137 Sn and 136-137 Sb have been presented. The present calculation favour a 2 -ground state for 136 Sb instead of 1 -identified through β-decay. Interesting observation about the E2 effective charges for this region has been discussed.

We present a systematic study of the electronic properties and the geometric structure of noble metal clusters X n (X = Cu, Ag, Au; =-1,0, +1; n ഛ 13 and n =20), obtained from first-principles generalized gradient approximation density functional calculations based on norm-conserving pseudopotentials and numerical atomic basis sets. We obtain planar structures for the ground state of anionic ͑ =-1͒, neutral ͑ =0͒, and cationic ͑ =1͒ species of gold clusters with up to 12, 11, and 7 atoms, respectively. In contrast, the maximum size of planar clusters with =-1,0, +1 are n = ͑5,6,5͒ for silver and (5,6,4) for copper. For X 20 we find a T d symmetry for gold and a compact C s structure for silver and copper. Our results for the cluster geometries agree partially with previous first-principles calculations, and they are in good agreement with recent experimental results for anionic and cationic gold clusters. The tendency to planarity of gold clusters, which is much larger than in copper and silver, is strongly favored by relativistic effects, which decrease the s-d promotion energy and lead to hybridization of the half-filled 6s orbital with the fully occupied 5d z 2 orbital. That picture is substantiated by analyzing our calculated density matrix for planar and three-dimensional clusters of gold and copper. The trends for the cohesive energy, ionization potentials, electron affinities, and highest accupied and lowest unoccupied molecular orbital gap, as the cluster size increases, are studied in detail for each noble metal and rationalized in terms of two-and three-dimensional electronic shell models. The most probable fragmentation channels for X n clusters are in very good agreement with available experiments.

The 49 Ti nucleus, with two protons and one neutron hole outside the doubly magic 48 Ca, constitutes a very good test for shell-model calculations. The studies of gamma decay of 49 Ti have been previously published in many works based on two ways: on accelerator and on reactor. The results on 50 V(t, ) 49 Ti, 50 Ti(d, t) 49 Ti, 48 Ca(, 3n) 49 Ti showed spin and parity of 49 Ti ground state was 7/2 -and compound state was 1/2 + . Those results provided 05 MeV energy arrange. Activation of 48 Ti by neutron was the method which was usually to do on the nuclear reactor. Those previous studies showed gamma rays, levels… more than research on accelerator . The same results in two ways of study were agreed with spin and parity of 49 Ti at compound state and ground state. Almost previous works used a Multi Channel Analysis (MCA) system to got experimental data that could not determine gamma cascade energy, intensity of a pair of gamma cascades which were determined by Ritz algorithms.The lifetime of these levels: 1381 keV (<5ps), 1585 keV (<11ps) and 1762 keV (<14 ps) were determined [2], but high levels were incomplete. In this experiment, to get experimental data by gamma-gamma coincidence system which treats by SACP method therefore it reduced background effectively.

The majority of navigation satellite receivers operate on a single frequency. They compensate for the ionospheric delay using either an ionospheric model which typically only corrects for 50% of the delay or a thin-shell map of the ionosphere. A 4D tomographic imaging technique is used to map the free electron density over the fullheight of the ionosphere above North America during autumn 2003. The navigation solutions computed using correction based upon the thin-shell and the full-height maps are compared in this paper. The maps are used to calculate the excess propagation delay on the L1 frequency experienced by GPS receivers at selected locations across North America. The excess delay is applied to correct the single-frequency pseudorange observations at each location, and the improvements to the resulting positioning are calculated. It is shown that the thin-shell and full-height maps perform almost as well as a dual-frequency carriersmoothed benchmark and for most receivers better than the unfiltered dual-frequency benchmark. The full-height corrections perform well and are considerably better than thinshell corrections under extreme storm conditions.

The core polarization charge of the E2 transition from the first excited 3/2-state to the 7/2-ground state of 41 Ca is calculated in the first-order perturbation theory by using the wave functions of a Woods-Saxon potential and compared with the results of harmonic oscillator potential. The contributions from the particle-hole excitations to continuum particle states, which constitute the major part of the excitations, are calculated explicitly. The resultant first-order core polarization charge in the Woods-Saxon shell model with a t-function type effective interaction 0.283e is smaller than the one of the harmonic oscillator shell model 0.3lle. The effects of the continuum states are discussed in comparison with the harmonic oscillator shell model.

The core polarization charge of the E2 transition from the first excited 3/2-state to the 7/2-ground state of 41 Ca is calculated in the first-order perturbation theory by using the wave functions of a Woods-Saxon potential and compared with the results of harmonic oscillator potential. The contributions from the particle-hole excitations to continuum particle states, which constitute the major part of the excitations, are calculated explicitly. The resultant first-order core polarization charge in the Woods-Saxon shell model with a t-function type effective interaction 0.283e is smaller than the one of the harmonic oscillator shell model 0.3lle. The effects of the continuum states are discussed in comparison with the harmonic oscillator shell model.

The knowledge of the level density as a function of excitation energy and nuclear spin is necessary for the description of nuclear reactions and in many applied areas. We discuss the level density problem as a part of the general understanding of mesoscopic systems with strong interactions. The underlying physics is that of quantum chaos and thermalization which allows one to use statistical methods avoiding full diagonalization. The resulting level density is well described by the constant temperature model in agreement with experimental data. We discuss the effective temperature parameter and show that it is not related to the pairing phase transition being analogous to the limiting temperature in particle physics. Other aspects of underlying physics include the collective enhancement of the level density, random coupling of individual spins and the role of incoherent collision-like interactions.

We performed the β decay spectroscopy on 24 Si in order to study the behavior of a weakly-bound s-wave proton. The behavior of a weaklybound proton in a proton-rich nucleus is one of the interesting topics to explore exotic nuclear structures such as proton halo. Thomas-Ehrman shift of the proton s 1/2 orbital induces a configuration change in the wave function. The change can be investigated in terms of the mirror asymmetry for Gamow-Teller transition strengths B(GT) for a proton-rich nucleus of 24 Si. The experiment was carried out at the RIPS facility. In this presentation, we will report the experimental results. Discussion on the comparison with theoretical calculations which takes into account the Coulomb force and the Thomas-Ehrman shift is also given.

Electron captures are amongst the most important weak interaction rates related to the dynamics of stellar core collapse. They play a key role in the gravitational collapse of the core of a massive star triggering the supernova explosion. Titanium isotopes are believed to have significant impact on controlling the lepton-to-baryon fraction in the late phases of evolution of core of massive stars. This work consists of the calculation of electron capture rates on titanium isotopes. The pn-QRPA theory is used to calculate electron capture rates in stellar matter. The electron capture rates are calculated over a wide range of densities (10 ≤ ρY e (g cm -3 ) ≤ 10 11 ) and temperatures (10 7 ≤ T (K) ≤ 30 ×10 9 ). Here we also report the differences in electron capture rates with the earlier calculations including those using large scale shell model.

We study the classical statistical mechanics of a shell-model chain with a quartic electron-ion in- teraction in one ionic species. In order to avoid long-range interactions generated by the adiabatic treatment of the shells, we assign them a finite mass. Under integration of the harmonic degrees of freedom, the partition function is shown to correspond to an etfective P model. This allows us to apply the transfer-integral technique for calculation of the free energy in the displacive limit. For the continuum we obtain exact kinktype solutions of the equations of motion. These excitations, to- gether with phonons which represent oscillations about kink configurations, are considered as in- teracting quasiparticles for the construction of the free energy, thus reobtaining the exact results in the low-temperature limit. This approach allows the extension of our results to the adiabatic case.

This work presents a fully nonlinear Kirchhoff-Love shell model. In contrast with shear flexible models, our approach is based on the Kirchhoff-Love theory for thin shells, so that transversal shear deformation is not accounted for. We define energetically conjugated cross-sectional generalized stresses and strains. The fact that both the first Piola-Kirchhoff stress tensor and the deformation gradient appear as primary

The take into account of the three-body monopole effects can solve the spectroscopic problems involved in certain nuclear properties, for which the two body realistic interactions failed. In order to study and to understand the role of these effects, calculations in the shell model of nuclear structure were carried out to develop the two body matrix elements of N-N interaction. Their application on 136 Sb nucleus with four valence particles in addition to the inert core 132 Sn has a great importance. This nucleus with N 82 is currently the most experimentally studied in this mass region. The first excited state, dominated by (1g7/2) 1 (2f7/2) 3 configuration, obtained in this work reproduces the experimental one.

In order to understand the monopole interaction effect on the single particle energies and the shell evolution, we have studied Z=51 isotopes with odd mass number in the vicinity of 132Sn mass region. We have performed some spectroscopic calculations in the framework of nuclear shell model using kh5082 and mkh effective interactions in a truncated space, which is constructed taking into account the evolution of the effective single particle energies in the studied mass region.

The take into account of the three-body monopole effects can solve the spectroscopic problems involved in certain nuclear properties, for which the two body realistic interactions failed. In order to study and to understand the role of these effects, calculations in the shell model of nuclear structure were carried out to develop the two body matrix elements of N-N interaction. Their application on 136 Sb nucleus with four valence particles in addition to the inert core 132 Sn has a great importance. This nucleus with N~ 82 is currently the most experimentally studied in this mass region. The first excited state, dominated by p(1 g 7/2 ) 1 n(2 f 7/2 ) 3 configuration, obtained in this work reproduces the experimental one

The spectra of nuclides involving few valence particles or holes far from β -stability are important tools to develop our knowledge about nuclear forces and N-N interaction. In order to understand the monopole interaction effect on the properties of nuclear structure of these nuclei, we have performed shell model calculations using recent experimental single particle energies, by means of Oxbash nuclear structure code. The two-body matrix elements of the effective interaction were deduced from those of kh5082 original interaction, taking into account the nuclear monopole effect in 132 Sn mass region. The obtained spectroscopic properties for 134 Te nucleus are in good agreement with the experiment.

We report the first no-core shell model results for 48 Ca, 48 Sc and 48 T i with derived and modified two-body Hamiltonians. We use an oscillator basis with a limited hΩ range around 45/A 1/3 -25/A 2/3 = 10.5M eV and a limited model space up to 1 hΩ. No single-particle energies are used. We find that the charge dependence of the bulk binding energy of eight A = 48 nuclei is reasonably described with an effective Hamiltonian derived from the CD-Bonn interaction while there is an overall underbinding by about 0.4 MeV/nucleon. However, the resulting spectra exhibit deficiencies that are anticipated due to: (1) basis space limitations and/or the absence of effective many-body interactions; and, (2) the absence of genuine three-nucleon interactions. We then introduce additive isospin-dependent central terms plus a tensor force to our Hamiltonian and achieve accurate binding energies and reasonable spectra for all three nuclei. The resulting no-core shell model opens a path for applications to the double-beta (ββ) decay process.

Recent results from neutrino oscillation experiments have convincingly demonstrated that neutrinos have mass and they can mix. The neutrinoless double beta ($0\ nu\ beta\ beta $) decay is the most sensitive process to determine the absolute scale of the neutrino ...

The Gammasphere spectrometer, in conjunction with the Microball charged-particle array, was used to investigate high-spin states in 112 Te via 58 Ni( 58 Ni, 4pγ ) reactions at 240 and 250 MeV. Several smooth terminating bands were established, and lifetime measurements were performed for the strongest one using the Doppler-shift attenuation method. Results obtained in the spin range 18-32h yield a transition quadrupole moment of 4.0 ± 0.5eb, which corresponds to a quadrupole deformation ε 2 = 0.26 ± 0.03; this value is significantly larger than the ground-state deformation of tellurium isotopes. It was also possible to extract a transition quadrupole moment for the yrast band in 114 Xe, produced via the 58 Ni( 58 Ni, 2pγ ) reaction. A value of 3.0 ± 0.5 eb was found in the spin range 16-24h, which corresponds to a quadrupole deformation ε 2 = 0.19 ± 0.03. Cranked Nilsson-Strutinsky calculations are used to interpret the results.

Bu calismada,128,130 Te izotoplarinin iki-notrinolu cift bozunumu (2νββ) icin nukleer matris elemanlari,yuk alisverisli etkilesmeyi parcacik-desik kanalinda dikkate alarak, Tamm-Dancoff Yaklasimi’nin (TDA) eziduler teoremiyle birlikte kullanilmasiyla hesaplandi. Hesaplamalar, kuresel cekirdek durumunda, Hartre Fock Yaklasimi’ni Sykrme-III kuvvetleri ile birlikte kullanarak elde edilen tek parcacik enerjileri bazinda yapildi.. Elde edilen sonuclar bu tip tek parcacik bazinin cift beta bozunumu nukleer matris elemani hesabinda alternatif bir yaklasim olarak kullanilabilecegini gostermektedir.

He received his Dr. Eng. in 2000 from Waseda University and is currently analyzing and developing ionospheric algorithms for Japanese MSAS program. He is a member of the MSAS Technical Review Board of JCAB. Keisuke Matsunaga is a Researcher of Electronic Navigation Research Institute. He received his M. Sc. in 1996 from Kyoto University and worked for the development of LSI at Mitsubishi Electric Corporation from 1996 to 1999. He joined ENRI in 1999, and is currently studying ionospheric scintillation effects on MSAS. He is a member of the MSAS Technical Review Board of JCAB. Kazuaki Hoshinoo is a Principal Researcher of Electronic Navigation Research Institute. He is the director of MSAS research program in ENRI and is a member of the MSAS Technical Review Board of JCAB. He chairs Ionosphere Working Group of the Board.

Single-frequency based Satellite-Based Augmentation Systems (SBAS), the augmentation of the Global Navigation Satellite System (GNSS), broadcast estimates of vertical ionospheric delays and confidence bounds on the delay errors at Ionospheric Grid Points (IGPs). Using an ionospheric irregularity undersampled threat model, the integrity bounds, called Grid Ionospheric Vertical Errors (GIVEs), must be augmented to bound ionospheric irregularity threats which may exist between or beyond Ionospheric Pierce Points (IPPs) under ionospheric storm conditions. Since the ionospheric disturbed conditions can vary significantly from one region to another region, threat models need to be built for regions where SBAS will be operational. This paper presents a new method for constructing an undersampled threat model for SBAS in the Korean region, examines the influence of threat model to system availability, and demonstrates the performance of a newly developed threat model. The existing method ta...

The presence of not yet detected intruder states in 8 Be e.g. a J = 2 + intruder at 9 M eV excitation would affect the shape of the β ∓ -delayed alpha spectra of 8 Li and 8 B. In order to test the plausibility of this assumption, shell model calculations with up to 4hω excitations in 8 Be (and up to 2hω excitations in 10 Be) were performed. With the above restrictions on the model spaces, the calculations did not yield any low-lying intruder state in 8 Be. Another approach -the simple deformed oscillator model with self-consistent frequencies and volume conservation gives an intruder state in 8 Be which is lower in energy than the above shell model results, but its energy is still considerably higher than 9 M eV .

In this work we examine two recent effective shell model interactions, JUN45 and JJ4B, that have been proposed for use in the f 5/2 , p 3/2 , p 1/2 , g 9/2 model space for both protons and neutrons. We calculate a number of quantities that did not enter into the fits undertaken to fix the parameters of both interactions. In particular we consider static quadrupole moments (Q's) of excited states of the even-even 70-76 Ge isotopes, as well as the B(E2) values in these nuclei. (We have previously studied 70 Zn isotopes using JJ4B.) Some striking disagreements between the JUN45 prediction and the experimental results had already been noted for the quadrupole moments of the 2 + 1 states of these nuclei. We investigate whether these discrepancies also occur for the JJ4B interaction. Subsequently, we also apply both interactions to calculate the Q's of some more highly excited states and compare the two sets of predictions regarding the nature of the nuclear states under consideration. In order to gain insight into these more complex large-scale shell-model calculations, we examine the corresponding and much simpler single-j shell model calculations in the g 9/2 neutron shell.

We study the cross-correlation between the spin and orbital parts of magnetic dipole transitions M 1 in both isoscalar and isovector channels. In particular, we closely examine certain cases where B(M 1) is very close to B(M 1) σ + B(M 1) l , implying a cancellation of the summed interference terms. We gain some insight into this problem by considering special cases approaching the SU (3) limit, and by examining the behaviour of single-particle transitions at the beginning and towards the end of the s -d shell.

In calculations of isoscalar magnetic moments of odd-odd N=Z nuclei it was found that for medium to heavy mass nuclei large-scale shell model calculations yielded results which were very close to those obtained with the much simpler single-j shell model. To understand this we compare isoscalar and isovector core-polarization configuration-mixing contributions to the magnetic moments-of-mirror pairs in first order perturbation theory, using a spin dependent delta interaction.We fit the strength of the delta interaction by looking at isovector and isoscalar mirror pairs. We then use the same interaction to calculate corrections due to first order core polarization of the magnrtic moments of odd-odd nuclei.

Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion 1 ADAM KLECZEWSKI, NORVAL FORTSON, BORIS BLINOV, University of Washington -Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment Ω much larger than expected from the nuclear shell model [1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba + , should resolve Ω with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S 1/2 to 5D 3/2 and 6S 1/2 to 5D 5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems.

Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion 1 ADAM KLECZEWSKI, NORVAL FORTSON, BORIS BLINOV, University of Washington -Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment Ω much larger than expected from the nuclear shell model [1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba + , should resolve Ω with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S 1/2 to 5D 3/2 and 6S 1/2 to 5D 5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems.

Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment phi much larger than expected from the nuclear shell model[1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba^+, should resolve phi with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S1/2 to 5D3/2 and 6S1/2 to 5D5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems. [1] V. Gerginov, A. Derevianko, and C. E. Tanner, Phys. Rev. Lett. 91, 072501 [2] K. Beloy,...

We report the results of an experiment in which we studied the near-yrast states in selenium isotopes approaching N = 50 following their population in multinucleon transfer reactions between a 82 Se beam and a 192 Os target. The level schemes for 80,82 Se derived from the current work are compared with restricted-basis shell-model calculations and pair-truncated shell-model calculations. These provide a good description of the yrast sequences in these nuclei using a basis space limited to excitations in the ν(p 3 2 , p 1 2 , g 9 2

The association behavior, critical micellization concentration (CMC), and enthalpy of demicellization (∆H demic ) of bovine β-casein were studied, for the first time by isothermal titration calorimetry, in a pH 7.0 phosphate buffer with 0.1 ionic strength and in pure water. In the buffer solutions, the CMC decreased asymptotically from 0.15 to 0.006 mM as the temperature was raised from 16 to 45 °C. ∆H demic decreased with increasing temperature between 16 and 28 °C but increased from 28 to 45 °C. Thermodynamic analysis below 30 °C is consistent with the Kegeles shell model, which suggests a stepwise association process. At higher temperatures, this model exhibits limitations, and the micellization becomes much more cooperative. The CMC values in water, measured between 17 and 28 °C, decreased with increasing temperature and, expectedly, were higher than those found in the buffer solutions. β-Casein micelles were visualized and characterized, for the first time in their hydrated state, using advanced digital-imaging cryogenic transmission electron microscopy. The images revealed small, oblate micelles, about ∼13 nm in diameter. The micelles shape and dimensions remained nearly constant in the temperature range of 24-35 °C.

Theoretical investigation of positive parity yrast band of odd-odd 130 Pr nucleus is performed by applying the projected shell model. The present study is undertaken to investigate and verify the very recently observed side band in 130 Pr theoretically in terms of quasi-particle (qp) configuration. From the analysis of band diagram, the yrast as well as side band are found to arise from two-qp configuration πh 11/2 ⊗ νh 11/2 . The present calculations are viewed to have qualitatively reproduced the known experimental data for yrast states, transition energies, and B(M1) / B(E2) ratios of this nucleus. The recently observed positive parity side band is also reproduced by the present calculations. The energy states of the side band are predicted up to spin 25 + , which is far above the known experimental spin of 18 + and this could serve as a motivational factor for future experiments. In addition, the reduced transition probability B(E2) for interband transitions has also been calculated for the first time in projected shell model, which would serve as an encouragement for other research groups in the future.

My area of research is Nuclear Theoretical Physics. I have joined research in this field as M.Phil scholar in the year 2011 and now, I am Pursuing my Ph.D in the same field from University of Jammu. I have published seven research paper so far, six in international journal and one in national journal. I have also presented fourteen research papers in various international and national conferences. I have also performed research as Junior Research Fellow and Senior Research fellow. I have research experience of six years. Awards and Achievements

The Hartree-Bogoliubov (HB) framework of calculations has been applied for calculating various nuclear structure quantities for 154-166 Dy mass chains. In this framework, the intrinsic quadrupole moments, the low-lying yrast states (E + 2 and E + 4 ) and occupation numbers for various shell model orbits have been obtained. The calculated results indicate that the observed onset of deformation in going from 154 Dy to 166 Dy arises due to enhanced occupation of (h 11/2 )π orbit, increased polarization of (d 5/2 )π orbit and increase in the occupation of down-slopping 'k' components of (i 13/2 )υ and (h 9/2 )υ orbits.

Neutron–rich nuclei in the A≈100 mass region have been the subject of many experimental studies because these nuclei exhibit a competition between spherical and deformed shapes. Light neutron-rich odd neutron N=63 isotones with A≈100 can be cited as one ...

Variation-after-projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for A = 98-106 strontium isotopes. In this framework, the yrast spectra with J Π ≥ 10 + , B(E2) transition probabilities, quadrupole deformation parameter and occupation numbers for various shell model orbits have been obtained. The results of the calculation for yrast spectra give an indication that it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in Sr isotopes. Besides this, it is also found that the simultaneous polarization of p 3/2 and f 5/2 proton subshells is a significant factor in making a sizeable contribution to the deformation in neutron-rich Sr isotopes.

A coherent state technique is used to generate an Interacting Boson Model (IBM) Hamiltonian energy surface which is adjusted to match a mean field energy surface. This technique allows for calculation of IBM Hamiltonian parameters, prediction of properties of low lying collective states, as well as generation of probability distributions of various shapes in the ground state of transitional nuclei. The last two of which are of astrophysical interest. The results for krypton, molybdenum, palladium, cadmium, gadolinium, dysprosium and erbium nuclei are compared with experiment.

Relativistic Mean Field calculations predict that the 02 + bands of Er and Yb isotopes around N=90 and 92 have a deformation of 2 ~ 0.45 and  ~ 10. This is a rather fascinating prospect since 02 + bands, which are nominally β-vibrational bands, will have a similar deformation to bands at high-spin in this region, which have been identified as "triaxial superdeformed bands". The calculations are supported by the large observed moments-of-inertia of the "-bands" in these nuclei, but Coulomb Excitation and Recoil Distance Doppler Shift techniques would give a direct measure of the deformation of these bands, including the triaxiality parameter . This Letter of Intent asks for the development of 160,162,164 Yb beams, to check the maximum achievable intensities, and beam contaminants, for Coulomb excitation and plunger measurements of the "-bands".

In β-decay experiments on 9 C at CERN/ISOLDE the β-strength was determined to the ground state, the 12.2 MeV excited state and the Isobaric Analog State (IAS) at 14.655 MeV in 9 B. A large β-strength asymmetry is deduced for the mirror transitions of 9 C and 9 Li to states around 12 MeV excitation energy. A satisfactory description of the three-body decay from a narrow energy region around the 12.2 MeV resonance is obtained within a sequential model involving the ground and first-excited states of 5 Li and 8 Be. From the study of angular correlations the spin of the 12.2 MeV state is determined as 5/2 -. For the first time the population of the IAS is observed in β-decay and new information on the decay of this state is obtained. The advantages of a closely packed, highly segmented detector setup are demonstrated.

The γ decay of the nuclei 124,125 Ba has been investigated by means of the EUROBALL spectrometer, coupled to the DIAMANT array of charged-particle detectors, using the reaction 64 Ni + 64 Ni at E beam = 255 and 261 MeV. In the nucleus 125 Ba six new E1 transitions have been found to link opposite-parity bands currently interpreted as νd 5/2 (+g 7/2 ), νh 11/2 structures. The previously unknown J π = 3 -level in the nucleus 124 Ba has also been identified; its excitation energy is accurately reproduced by a microscopic calculation including octupole correlations. Both issues are bolstered by sizable B(E1)/B(E2) ratios.