Fragmentation of twophonon {gamma}vibrational strength in deformed nuclei
Abstract
Rotational and vibrational modes of collective motion. are very useful in classifying the lowlying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and stronglyenhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in eveneven deformed nuclei, typically occurring at {approx}1 MeV, is classified as a onephonon {gamma}vibration state. In a pure harmonic vibration limit, the expected twophonon {gamma}vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with twoquasiparticle configurations. Therefore, the question of the localization of twophonon {gamma}vibration strength has been raised because mixing may lead to fragmentation of the twophonon strength over a range of excitation energy. For several welldeformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being twophonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two and onephonon states are the only unambiguous measure of double phononmore »
 Authors:

 Univ. of Rochester, NY (United States)
 Publication Date:
 Research Org.:
 Argonne National Lab., IL (United States)
 OSTI Identifier:
 458928
 Report Number(s):
 ANL/PHY97/1; CONF9607156
ON: DE97003376; TRN: 97:007001
 Resource Type:
 Conference
 Resource Relation:
 Conference: Conference on nuclear structure at the limits, Argonne, IL (United States), 2226 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the conference on nuclear structure at the limits; PB: 391 p.
 Country of Publication:
 United States
 Language:
 English
 Subject:
 66 PHYSICS; DEFORMED NUCLEI; OSCILLATION MODES; COLLECTIVE EXCITATIONS; NUCLEAR MODELS; OSCILLATOR STRENGTHS; FRAGMENTATION; ROTATION; PHONONS; VIBRATIONAL STATES
Citation Formats
Wu, C Y, and Cline, D. Fragmentation of twophonon {gamma}vibrational strength in deformed nuclei. United States: N. p., 1996.
Web.
Wu, C Y, & Cline, D. Fragmentation of twophonon {gamma}vibrational strength in deformed nuclei. United States.
Wu, C Y, and Cline, D. Tue .
"Fragmentation of twophonon {gamma}vibrational strength in deformed nuclei". United States. https://www.osti.gov/servlets/purl/458928.
@article{osti_458928,
title = {Fragmentation of twophonon {gamma}vibrational strength in deformed nuclei},
author = {Wu, C Y and Cline, D},
abstractNote = {Rotational and vibrational modes of collective motion. are very useful in classifying the lowlying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and stronglyenhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in eveneven deformed nuclei, typically occurring at {approx}1 MeV, is classified as a onephonon {gamma}vibration state. In a pure harmonic vibration limit, the expected twophonon {gamma}vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with twoquasiparticle configurations. Therefore, the question of the localization of twophonon {gamma}vibration strength has been raised because mixing may lead to fragmentation of the twophonon strength over a range of excitation energy. For several welldeformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being twophonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two and onephonon states are the only unambiguous measure of double phonon excitation. Such B(E2) data are available for {sup 156}Gd, {sup 160}Dy, {sup 168}Er, {sup 232}Th, and {sup 186,188,190,192}Os. Except for {sup 160}Dy, the measured B(E2) values range from 23 Weisskopf units in {sup 156}Gd to 1020 Weisskopf units in osmium nuclei; enhancement that is consistent with collective modes of motion.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {12}
}