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Title: Signature for rotational to vibrational evolution along the yrast line

Abstract

The excitation spectra of nuclei in the regions 150<A<190 and 220<A<250 are commonly considered as showing characteristics of the rotational motion. In the present work, however, there is evidence indicating that the nuclei can evolve from rotation to vibration. We have used two simple models to discuss the collective motions of a nucleus for different spin ranges. In addition, in order to get the insight into the rotational-like properties of nuclei, as an example, shape calculations using the total Routhian surfaces (TRS) model have been carried out for positive-parity states in {sup 156}Gd. Also we have shown the result of the nucleus {sup 102}Ru which is given as an example of the reverse transition, i.e., vibration to rotation. The TRS plots reveal that, with increasing spin, the former nucleus becomes slightly soft in {gamma} and {beta} deformations, while the latter one becomes rigid in the {gamma} deformation.

Authors:
 [1];  [2]; ;  [3]; ;  [1];  [4]
  1. School of Physics and MOE Laboratory of Heavy Ion Physics, Peking University, Beijing 100871 (China)
  2. (China)
  3. School of Nuclear Engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi (China)
  4. Department of Physics, North University of China, Taiyuan 030051 (China)
Publication Date:
OSTI Identifier:
20995246
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevC.75.047304; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COLLECTIVE MODEL; EXCITATION; GADOLINIUM 156; MASS NUMBER; ROTATION; ROTATIONAL STATES; RUTHENIUM 102; SPIN; VIBRATIONAL STATES; YRAST STATES

Citation Formats

Shen, S. F., School of Nuclear Engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi, Chen, Y. B., Tang, B., Xu, F. R., Zheng, S. J., and Wen, T. D. Signature for rotational to vibrational evolution along the yrast line. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.047304.
Shen, S. F., School of Nuclear Engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi, Chen, Y. B., Tang, B., Xu, F. R., Zheng, S. J., & Wen, T. D. Signature for rotational to vibrational evolution along the yrast line. United States. doi:10.1103/PHYSREVC.75.047304.
Shen, S. F., School of Nuclear Engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi, Chen, Y. B., Tang, B., Xu, F. R., Zheng, S. J., and Wen, T. D. Sun . "Signature for rotational to vibrational evolution along the yrast line". United States. doi:10.1103/PHYSREVC.75.047304.
@article{osti_20995246,
title = {Signature for rotational to vibrational evolution along the yrast line},
author = {Shen, S. F. and School of Nuclear Engineering and Technology, East China Institute of Technology, Fuzhou 344000, Jiangxi and Chen, Y. B. and Tang, B. and Xu, F. R. and Zheng, S. J. and Wen, T. D.},
abstractNote = {The excitation spectra of nuclei in the regions 150<A<190 and 220<A<250 are commonly considered as showing characteristics of the rotational motion. In the present work, however, there is evidence indicating that the nuclei can evolve from rotation to vibration. We have used two simple models to discuss the collective motions of a nucleus for different spin ranges. In addition, in order to get the insight into the rotational-like properties of nuclei, as an example, shape calculations using the total Routhian surfaces (TRS) model have been carried out for positive-parity states in {sup 156}Gd. Also we have shown the result of the nucleus {sup 102}Ru which is given as an example of the reverse transition, i.e., vibration to rotation. The TRS plots reveal that, with increasing spin, the former nucleus becomes slightly soft in {gamma} and {beta} deformations, while the latter one becomes rigid in the {gamma} deformation.},
doi = {10.1103/PHYSREVC.75.047304},
journal = {Physical Review. C, Nuclear Physics},
number = 4,
volume = 75,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • We present a simple method for discerning the evolution from vibrational to rotational structure in nuclei as a function of spin. The prescription is applied to the yrast cascades in the A~110 region and a clear transition from vibrational to rotational motion is found.
  • It is shown that the anharmonic vibrator reproduces the ground band energies and {ital B}({ital E}2) values, not only of vibrational and transitional nuclei, but of good rotor nuclei, at least as well as other models, including those designed specifically for rotational nuclei.
  • States in /sup 154/Dy have been located up to I/sup ..pi../ = 48/sup +/ and their lifetimes measured. Marked structural changes occur along the yrast line with a transition from prolate to oblate shape, followed by an unexpected return to moderate collectivity at the highest spins. Structural changes with increasing energy above the yrast line are also observed.
  • Applying the measured incremental irradiance gain per unit plasma length for various input irradiances to the analytical formulas for a partially homogeneously broadened, saturated gain medium, the line shape parameters such as the small-signal gain, the saturation parameter, and the ratio of the Lorentzian to Doppler linewidths are obtained for individual vibrational-rotational transitions of a CO/sub 2/ laser amplifier. It is found that the homogeneous broadening becomes predominant across the lines with a higher gain, while the inhomogeneous broadening is emphasized across the remote lines with a lower gain from the central line for both 10 P and R branches.more » Pressure and discharge-current dependence on the lineshape parameter are also investigated for the typical two lines, i.e., 10 P-20 and -12 lines, together with discussions.« less
  • A dual-polarization CO/sub 2/ laser can be caused to operate such that the two polarization modes correspond, respectively, to different rotational-vibrational lines. Interline competition effects, similar to those described previously, here also result in a mode power change with optical frequency which can be utilized as a convenient and sensitive optical frequency discriminant.