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The dependence of reduced transition probabilities corresponding to electric quadrupole [B(E2)] and magnetic dipole [B(M1)] transition occurring in 1 8 F nucleus on excitation energy and spin parity of the states involved in the transition has been investigated within the framework of simple potential model based on M3Y interaction. It is found that B(E2) increases with increasing excitation energy irrespective of the spin of excited states while B(M1) is very sensitive to the spin of the excited states and is independent of excitation energy. [ABSTRACT FROM AUTHOR]

I have used a simple two-state model to fit E2 strengths connecting the first two 0 + states to the first two 2 + states in 98 Sr. Results for mixing parameters are in excellent agreement with those from a recent analysis. Perhaps surprisingly, they are also in remarkable agreement with results from 1980, despite the wide variation reported in the intervening years. [ABSTRACT FROM AUTHOR]

Lineshapes for the electromagnetically induced absorption (EIA) of thermal 85 Rb atoms in a degenerate two-level system have been investigated using matching ( σ ∥ σ , π ∥ π ) and orthogonal ( σ ⊥ σ , π ⊥ π ) polarization configurations of coupling and probe beams. EIA signals, which result from coherence population oscillation and transfer of coherence of the excited state, are obtained in detail theoretically and experimentally. The observed EIA linewidths, which are limited due to the decoherence rate between the magnetic sublevels in the ground state from transit-time relaxation, match well with the calculated ones. Decompositions of the absorption signals analyzed with respect to magnetic sublevels of the ground state show that enhanced or decreased absorption signals for each component of magnetic sublevels in the ground state depend on several factors. These factors include the decay rates and transition strengths, which determine the overall absorption spectral profile. [ABSTRACT FROM AUTHOR]

Background: In neutron-rich nuclei around N=40 rapid changes in nuclear structure can be observed. While Ni68 exhibits signatures of a doubly magic nucleus, experimental data along the isotopic chains in even more exotic Fe and Cr isotopes-such as excitation energies and transition strengths-suggest a sudden rise in collectivity toward N=40. Purpose: Reduced quadrupole transition strengths for low-lying transitions in neutron-rich 58,60,62Cr are investigated. This gives quantitative new insights into the evolution of quadrupole collectivity in the neutron-rich region close to N=40. Method: The recoil distance Doppler-shift (RDDS) technique was applied to measure lifetimes of low-lying states in Cr58,60,62Cr. The experiment was carried out at the National Superconducting Cyclotron Laboratory (NSCL) with the SeGA array in a plunger configuration coupled to the S800 magnetic spectrograph. The states of interest were populated by means of one-proton knockout reactions. Results: Data reveal a rapid increase in quadrupole collectivity for 58,60,62Cr toward N=40 and point to stronger quadrupole deformations compared to neighboring Fe isotopes. The experimental B(E2) values are reproduced well with state-of-the-art shell-model calculations using the LNPS effective interaction. A consideration of intrinsic quadrupole moments and B42 ratios suggest an evolution toward a rotational nature of the collective structures in 60,62Cr. Compared to 58Cr, experimental B42 and B62 values for 60Cr are in better agreement with the E(5) limit. Conclusion: Our results indicate that collective excitations in neutron-rich Cr isotopes saturate at N=38, which is in agreement with theoretical predictions. More detailed experimental data of excited structures and interband transitions are needed for a comprehensive understanding of quadrupole collectivity close to N=40. This calls for additional measurements in neutron-rich Cr and neighboring Ti and Fe nuclei. [ABSTRACT FROM AUTHOR]