Giant resonances and bound collective states observed in the scattering of 92.5-MeV electrons from the closed-neutron-shell nucleus Y89 between excitation energies from 2.0 to 55 MeV

Download
Author
Pitthan, R.
Buskirk, F.R.
Dally, E.B.
Shannon, J.O.
Smith, W.H.
Date
1977-09Metadata
Show full item recordAbstract
92.5 MeV electrons were used to study in (89)Y the excitation range between 2 and 55 MeV. Above neutron threshold, broad electric resonances have been seen at 14.0 (63A(-1/3) MeV (E2, vT = 0) and 28 (125A-(1/3) MeV (E2, vT = 1). The total width of the isoscalar E2 resonance is (4.5 +/-0.4) MeV and its strength (56 =/- 6) % energy-weighted sum rule (E2, vT = 0). For the isovector E2 resonance only a minimal value of 7 MeV for the width can be given which is connected with (48 +/- 5)% of the isovector sum rule. The strength of the E1 resonance [T>7(104 =/- 10)% of the Thomas-Reiche-Kuhn sum rule] agrees well with (y,n) measurements, thus giving a check for the accuracy of the evaluating methods employed. A structure around 19-20 MeV, believed to be the T> part of the giant dipole resonance, carries (8 +/- 3)% of the E1 sum rule. In addition to these generally well known states, clustering of E3 strength, (13 +/- 2)% energy-weighted sum rule (E3, vT = 0), was found at 6.75 and 80.5 MeV; the enveloping line shape of these clusters was best described by a Breit-Wigner term. Other concentrations of strength include E3 at 2.6 MeV, (15 +/-3)% energy-weighted sum rule E3, (vT = 0), E2 at 4.0 MeV, (11 +/- 3)% energy-weighted sum rule (E2, vT = 0), and E3 strength at 13.5 MeV. No resonance other than the E1 was found around 17 MeV, thus ruling out in (89)Y the existence of a monopole state with 100% sum rule proposed for (90)Zr from (a,a') and (e,e') measurements. In contrast to heavy nuclei, no resonant 3hw E3 strength could be located.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.Collections
Related items
Showing items related by title, author, creator and subject.
-
Giant multipole resonances in the deformed fissionable nucleus 238U
Pitthan, R.; Buskirk, F.R.; Houk, W.A.; Moore, R.W. (American Physical Society, 1980-01);The deformed, fissionable nucleus 238U was studied with inelastic scattering of 87.5 MeV electrons between 5 and 40 MeV excitation energy with inelastic momentum transfers ranging from 0.32 fm ' to 0.58 fm ' for an excitation ... -
Giant multipole resonances in the deformed fissionable nucleus 238U: breakdown of the hydrodynamical models?
Pitthan, R.; Buskirk, F.R.; Houk, W.A.; Moore, R.W. (Monterey, California. Naval Postgraduate School, 1980);The deformed, fissionable nucleus 238u was studied with inelastic scattering of 87.5 MeV electrons between 5 and 40 MeV excitation energy with inelastic momentum transfers ranging from 0.32 fm -1 to 0.58 fm -1 for an ... -
E0, El, E2, E3, and E4 giant resonances in the N = 82 nucleus (140) Ce between 4 and 48 MeV excitation energy with inelastic electron scattering
Pitthan, R.; Hass, H.; Meyer, D.H.; Buskirk, F.R.; Dyer, J.N. (American Physical Society, 1979-04);The cross section for electron scattering from natural cerium (89% 14°Ce) has been measured with electrons of 80 and 92 MeV at 90 and 105° between 4 and 48 MeV excitation energy. The nine resonances ...