Effect of multiple scattering on broadening and the frequency shift of spectral lines

The effect of multiple scattering on the broadening and the shift of the spectral lines of light propagating in a medium is investigated within Wolf's framework. The condition for no blueshift is derived. It is shown that under the same hypothesis the property Δ ωN+1≫+ δ N is satisfied. Moreover, the no blueshift condition has been found to be closely related to the no blurring condition. These results might be of relevance in the astronomical domain. © 1998 The American Physical SocietyM.M. acknowledges financial support by DGICYT (Spain); Grant No. PB93-0139.Peer Reviewe

Experiences of overseas trained teachers seeking public school positions in Western Australia and South Australia

Many overseas trained teachers migrate to Australia in search of different lifestyles. In their endeavour to find suitable teaching positions in public secondary schools, overseas trained teachers often confront multiple challenges. This study explored the different issues that 12 overseas trained teachers experienced before obtaining a teaching position in a public secondary school in either Western Australia or South Australia. Data were collected through using twelve in-depth semi-structured interviews and researcher generated field notes. The results indicate that participants experienced the following challenges: apparent lack of information on post immigration life in Australia; danger of misinformation; registration delays; inconsistency in English language requirements; fixed term offers for teaching positions; difficult living conditions in the country areas; and a perceived lack of consistency in the teacher orientation programs provided by the Education Departments of Western Australia and South Australia

Broadening of Spectral Lines due to Dynamic Multiple Scattering and the Tully-Fisher Relation

The frequency shift of spectral lines is most often explained by the Doppler Effect in terms of relative motion, whereas the Doppler broadening of a particular line mainly depends on the absolute temperature. The Wolf effect on the other hand deals with the correlation induced spectral change and explains both the broadening and shift of the spectral lines. In this framework a relation between the width of the spectral line is related to the redshift z for the line and hence with the distance. For smaller values of z a relation similar to the Tully-Fisher relation can be obtained and for larger values of z a more general relation can be constructed. The derivation of this kind of relation based on dynamic multiple scattering theory may play a significant role in explaining the overall spectra of quasi stellar objects. We emphasize that this mechanism is not applicable for nearby galaxies, $z \leq 1$.Comment: 18 pages, 5 figures, revised Version has been submitted to Physical Review A. (2nd author's affiliation corrected

Systematics of Anti magnetic rotation in even-even Cd isotopes

The lifetimes for the high spin levels of the yrast band of $^{110}$Cd has been measured. The estimated B(E2) values decrease with increase in angular momentum. This is the characteristic of Anti magnetic rotation as reported in $^{106,108}$Cd. However, alignment behavior of $^{110}$Cd is completely different from its even-even neighbors. A model based on classical particle plus rotor has been used to explore the underlying systematics and develop a self consistent picture for the observed behavior of these isotopes.Comment: 18 pages including 6 figures. Accepted to be published in PLB, with some modification in the tex

Coupled channel description of 16O+142,144,146Nd scattering around the Coulomb barrier using a complex microscopic potential

Angular distributions of elastic scattering and inelastic scattering from 2+ 1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a 'hybrid' approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+ 1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods-Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. © 2003 Elsevier Science B.V. All rights reserved

Large diamagnetic persistent currents

In multichannel rings, evanescent modes will always co-exist with propagating modes. The evanescent modes can carry a very large diamagnetic persistent current that can oscillate with energy and are very sensitive to impurity scattering. This provides a natural explanation for the large diamagnetic persistent currents observed in experiments.Comment: 5 figure