APPENDIX NUCLEAR STRUCTURE 1. Spherical Shell Model The stability of certain combinations of neutrons and protons was pointed out by Elsasser1 in 1934. Stability for light nuclei with N or Z values of 2 (4He), 8 (16O), and 20 (40Ca) became well known, and in 1948 Mayer2 observed strong evidence for additional "magic numbers" at 50 and 82 for protons, and 50, 82, and 126 for neutrons. Mayer and Jensen3 explained this in terms of a "shell model", where nucleons moved in a spherically symmetric potential well. This potential is most commonly taken as a harmonic oscillator of the form V (r ) = −V 0 RQ1 − (r /R )2 HP, (1) where V(r) is the potential at a distance r from the center of the nucleus and R is the nuclear radius. The resulting quantum states can be characterized by n , the principal quantum number related to the number of radial nodes in the wave function, and by l , the orbital angular momentum of the particle. By analogy to atomic spectroscopy, states with l = 0, 1, 2, 3, 4, 5, 6, ... are designated as s ,p ,d , f ,g ,h ,i ,..., respectively. The states are identified by as 1s , 2f , 3p , etc, where, unlike in atomic spectroscopy, n is defined so that each state has n −1 radial nodes. .. The solution of the Schrodinger equation for the isotropic harmonic oscillator gives the level energies (2) E =− h ω [2(n − 1) + l ]+E , 0 0 where I ω0= J L 2V 0 hhhhh MR 2 1/2 M J , (3) O M is the nucleon mass, and E 0=3/2− h ω0. Here states with the same value of N =2(n −1)+l are degenerate, and states of a given energy must all have either even or odd values of l . Thus, degenerate states must have the same parity. Mayer4 and Haxel et al 5 showed that the interaction between the intrinsic angular momentum (spin) of the particles and their total angular momentum would split the orbitals into two substates with l ±1/2 (e.g. 1p 1/2 and 1p 3/2). These states are no longer degenerate, and it was shown that if the "spin-orbit" interaction is of the same order as the spacing between oscillator shells, and states with j =l +1/2 are more stable than states with j =l −1/2, then the magic numbers can be reproduced. The evolution of shell model states from the harmonic oscillator model is depicted in Figure 1. 2. Collective Model The shell model succeeds in describing nuclei near the magic numbers, but it fails to adequately describe nuclei outside the closed shells. This may be attributed to a breakdown in the assumption of spherical symmetry. Rainwater6 proposed that, in odd-A nuclei, the motion of the odd nucleon could polarize the even-even core allowing all nucleons to move collectively, thus increasing the static electric quadrupole moments and enhancing quadrupole transition (E 2) rates. The implications of spheroidal rather than spherical shape were studied by Bohr and Mottelson7 who developed a collective model for nuclei. For a spheroidal nucleus, the orbital angular momentum of the odd nucleon is no longer conserved. Since total angular momentum for the nuclear system must be conserved, the core must have angular momentum coupled to that of the odd nucleon. Addition of more nucleons outside the closed shells can hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh 1 W. Elsasser, J.Phys. Rad. 5, 625 (1934). 2 M.G. Mayer, Phys. Rev. 74, 235 (1948). 3 M.G. Mayer and J.H.D. Jensen, Elementary Theory of Nuclear Shell Structure, John Wiley & Sons, Inc., New York (1955). 4 M.G. Mayer, Phys. Rev. 78, 16 (1950). 5 O. Haxel, J.H.D. Jensen, and H.E. Suess, Z. Physik 128, 295 (1950). 6 L.J. Rainwater, Phys. Rev. 79, 432 (1950). 7 A. Bohr and B.R. Mottelson, Dan. Mat.-Fys. Medd. 27, No. 16 (1953); and "Collective Nuclear Motion and the Unified Model", Beta and Gamma Ray Spectroscopy , K. Siegbahn, editor, North Holland, Amsterdam (1955). 15/2[707] 13/2[716] 11/2[725] 9/2[734] 7/2[743] 5/2[752] 3/2[761] 1/2[770] 11/2[606] 9/2[604] 7/2[613] 5/2[622] 3/2[631] 1/2[640] 7/2[624] 5/2[633] 3/2[642] 1/2[651] 184 4s 3d 6 hω + 2g 3/2[602] 1/2[600] 1/2[611] 7/2[604] 5/2[602] 3/2[611] 1/2[620] 5/2[613] 3/2[622] 1/2[631] 1j15/2 3d3/2 4s1/2 2g7/2 1i11/2 3d5/2 2g9/2 1i 126 3p 2f 5 hω - 1i13/2 3p3/2 3p1/2 2f7/2 2f5/2 1h9/2 1h 3s 2d 4 hω + 2p 5/2[503] 3/2[501] ([512]) 1/2[510] ([521]) 11/2[505] 9/2[514] 7/2[523] 5/2[532] 3/2[541] 1/2[550] 82 1h11/2 3s1/2 2d3/2 2d5/2 1g7/2 1g 3 hω - 3/2[512] ([501]) 1/2[521] ([510]) 1/2[501] 13/2[606] 11/2[615] 9/2[624] 7/2[633] 5/2[642] 3/2[651] 1/2[660] 7/2[514] ([503]) 5/2[523] ([512]) 3/2[532] ([521]) 1/2[541] ([530]) 9/2[505] 7/2[503] ([514]) 5/2[512] ([523]) 3/2[521] ([532]) 1/2[530] ([541]) 1/2[411] ([400]) 3/2[402] ([402]) 1/2[400] ([411]) 5/2[413] ([402]) 3/2[422] ([411]) 1/2[431] ([420]) 7/2[404] 5/2[402] ([413]) 3/2[411] ([422]) 1/2[420] ([431]) 50 1g9/2 2p1/2 1f5/2 2p3/2 1/2[301] 5/2[303] 3/2[301] 1/2[310] 3/2[312] 1/2[321] 1f 9/2[404] 7/2[413] 5/2[422] 3/2[431] 1/2[440] 28 7/2[303] 5/2[312] 3/2[321] 1/2[330] 1f7/2 20 2 hω + 2s 1d 3/2[202] 1/2[200] 1/2[211] 5/2[202] 3/2[211] 1/2[220] 1d3/2 2s1/2 1d5/2 8 1 hω - 1p 1p1/2 1p3/2 1/2[101] 3/2[101] 1/2[110] Figure 1. Evolution of nuclear models from the harmonic oscillator model, adding strong spinorbit coupling to obtain the shell model, and axial deformation to give the collective model. Asymptotic Nilsson configurations are given for neutrons and, in parentheses, for protons when different. Because of mixing, very few states have pure Ω[NnzΛ] configurations. 2 0 hω + 1s Harmonic Oscillator N hω nl π 1s1/2 Shell Model nlj Collective Model Ω[NnzΛ]n ([NnzΛ]p) form spheroidal nuclei whose angular momentum states reflect the coherent motion of all nucleons rather than just a few nucleons moving in single-particle shell model orbitals. The quantization of this coherent motion forms the basis of the collective model. This collective motion can be quantized by assuming that the even-even core is an incompressible liquid and quantizing the classical hydrodynamical equations that describe its oscillations. Borrowing from the well-known analysis of rotational states in symmetric-top molecules, we expect the level energy relation − 2K 2 [J (J + 1) − K 2] hhhhhh h E =− h 2hhhhhhhhhhhhhh + (4) 2J_ 2J_ 1 3 1/2− where [J (J + 1)] h is the total angular momentum of the nucleus, and K − h is the component of angular momentum along the symmetry axis of the nucleus, as shown in Figure 2. _ J 1 and _ J 3 are the moments of inertia perpendicular and parallel to the symmetry axis, respectively. For low-lying rotational bands in even-even nuclei, K =0 and Eq. (4) reduces to [J (J + 1)] E =− h 2 hhhhhhhhh . 2J_ 1 (5) States with K ≠0 arise when one or more pairs of nucleons are broken and unpaired nucleons are excited to higher shell-model states. Low-lying rotational levels with K =0 are characterized by a sequence of states with J = 0, 2, 4, 6, 8, . . . and positive parity, often referred to as the ground-state (GS) band. An example of the GS band for 152Sm is shown in Figure 3. Excited vibrational states of three kinds are also shown for 152Sm in Figure 3. The β-vibration preserves spheroidal symmetry, and the γ-vibration goes through an ellipsoidal symmetry. The octupole vibration produces a low-lying J π=3− state in spherical nuclei, but can also couple to core quadrupole excitations in deformed nuclei to give a family of low-lying states with J π=1−, 2−, 3−,4−, and 5−. 3. Deformed Shell Model A unified model for the effect of deformation on shell-model states has been developed by Nilsson1 and by Mottelson and Nilsson2. The deformation breaks the 2 j + 1 degeneracy of the spherical shellmodel states. Asymptotic quantum numbers needed to describe these states are shown in Figure 2. In addition to K , they include N , the total oscillator shell quantum number; nz , the number of oscillator quanta in the z direction; M , the projection of total angular momentum J on the laboratory axis; R , the angular momentum from the collective motion of the nucleus; Ω, the projection of total angular momentum j (orbital l plus spin s ) of the odd nucleon on the symmetry axis; and Λ, the projection of angular momentum along the symmetry axis where Ω=Λ+Σ and Σ is the projection of intrinsic spin along the symmetry axis. Levels are labeled by the asymptotic quantum numbers Ωπ[Nnz Λ]. The Nilsson orbitals which derive from the axially deformed harmonic oscillator potential, labeled as described by Davidson3, are shown in Figure 1. A more realistic calculation can be performed using a Woods-Saxon potential V0 , (6) r −R 1+exp( hhhhh ) a where a ≈0.67 fm. Considerable mixing of Nilsson configurations with ∆Ω=0, ∆N=2, and similar excitation energies may occur leaving only Ω as a good quantum number. Representative Nilsson level diagrams, for various mass regions and deformations, calculated as described by Bengtsson and Ragnarsson4, are shown in Figures 4-14. In these figures, single-particle energies are plotted in units of the oscillator frequency V (r ) = hhhhhhhhhhhh − h ω0 = 41A −1/3 MeV (7) as a function of deformation ε2, with ε4 chosen as described in the figure captions. The Nilsson quadru∆R pole deformation parameter ε2 can be defined in terms of δ= hhhhhh where Rr.m.s. is the root mean Rr.m.s. hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh 1 S.G. Nilsson, Dan. Mat.-Fys. Medd. 29, No. 16 (1955). 2 B.R. Mottelson and S.G. Nilsson, Phys. Rev. 99, 1615 (1955). 3 J.P. Davidson, Collective Models of the Nucleus, Academic Press (1968). 4 T. Bengtsson and I. Ragnarsson, Nucl. Phys. A436, 14 (1985). Laboratory axis J R M j s l Λ is etry ax Symm Ω Σ K Figure 2. Asymptotic quantum numbers for the deformed shell model square nuclear radius and ∆R is the difference between the semi-major and semi-minor axes of the nuclear ellipsoid, as12 ε2 = δ + 1 2 hhh 5 3 hhhh 37 4 δ + δ + δ +.... 6 18 216 hh (8) The deformation parameter β2 is related to ε2 by I M 4 4 4 4 d dd β2 = √π /5 J hh ε2 + hh ε22 + hhh ε23 + hhh ε24 + . . . J 3 9 27 81 L O (9) The intrinsic quadrupole moment Q 0 (or transition quadrupole moment QT ∼ ∼Q 0) is related to β2 by dddddd Q 0 = √16π /5ZeR 02 β2. (10) If the partial photon half-life for the E2 transition is known, the experimental transition strength B (E 2) is given by 0.05659 B (E 2) = hhhhhhhhhhhh (eb )2, (11) t 1/2(E 2)(E γ)5 hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh 12 .. .. K.E.G. Lobner, M. Vetter, and V. Honig, Nucl. Data Tables A7, 495 (1970). where t 1/2(E 2) is in picoseconds, and E is in MeV. B (E 2) is related to Q 0 by 2 5 B (E 2) = B (JK →J −2 K ) = hhhh Q 02 <JK 20 | J −2 K > (eb )2. 16π (12) Assuming a constant charge distribution in the nucleus, Q 0=0 for spherical nuclei, Q 0>0 for prolate (football or cigar shaped) nuclei, and Q 0<0 for oblate (disk shaped) nuclei. The spectroscopic quadrupole moment Q is related to the intrinsic moment by 12 3K 2 − J (J + 1) Q = Q 0 hhhhhhhhhhhhhh . (J + 1)(2J + 3) (13) For M 1 transitions, the transition strength B (M 1) is given by 2 3 B (M 1) = B (JK →J ±1 K ) = hhh (gK −gR )2K 2<JK 10 | J ±1 K > µN2 , 4π (14) where gK and gR are nuclear g -factors. The rotational g -factor, gR , arises from the collective rotation of the core, and is defined as Z gR ≈ hh . A (15) The intrinsic g -factor, gK , arises from the orbital motion of the valence nucleons, and the total magnetic dipole moment is given by K2 µ = gR J + (gK − gR ) h hhh J +1 (16) If the partial photon half-life for the M 1 transition is known, then B (M 1) can be calculated from 14+ 2736.3 1666.48 Octupole band 6+ 4+ 2+ 0+ 706.96 288 213 1125.35 4+ 2+ 0+ 126 1041.180 963.376 8+ 418 1221.64 1310.51 1022.962 810.465 684.70 6+ 5+ 4+ 3+ 2+ 218 2139.7 326 356 484 8+ 6+ 340 1– 1609.34 1505.62 245 3– 2079.6 1879.1 122 5– 10+ 2375.5 (8+) 7+ 10+ 7– 2148.8 148 286 540 (9)+ 2327.1 12+ 9– 2525.6 235 12+ 11– 386 14+ 2976.7 446 2833.5 (17) 3362.3 451 (16+) 413 507 13– 3383.5 588 (15–) 626 0.0394 B (M 1) = hhhhhhhhhhh µN2 . t 1/2(M 1)E γ3 γ band β band 366.4814 121.7825 0 GS band 152 62Sm Figure 3. Ground-state, and β-, γ-, and octupole-vibrational bands in 152Sm. 1945.82 1728.38 1559.53 1371.752 1233.876 1085.897 1/2[420] 50 1/2 404] 9/2 [ [43 1] 7/2[413] 5.0 1] 1/2 [30 5/2[422] 1g9/2 5/2[303] 3/2 [4 2p1/2 31] 3/2[301] 1f5/2 4.5 1/2 1/2 [31 0] 2p3/2 3/2 [312] [44 0] 1/2 [32 1] 28 03] 7/2 [3 − ω) Es.p. (h 5/2[312] 1f7/2 4.0 3/2 [321 ] 1/2 [3 30] 20 3/2 [202] 1/2[200] 1d3/2 3.5 1/2[211] 2s1/2 5/2 [202] 3/2 [211] 1d5/2 1/2 [2 20] 3.0 8 1/2[101] 1p1/2 2.5 3/2 [101] 1p3/2 2.0 −.3 −.2 −.1 .0 1/2 [110] .1 .2 ε2 Figure 4. Nilsson diagram for protons or neutrons, Z, N ≤ 50 (ε4 = 0). .3 1/2[640] 3/2[761] 2[ 40 5/ ] 3 [770 [ /2 1/ [402 2[ ] 40 0] 1/2[521] 7/2[633] 2] 1/2 1] [65 ] 3/2 660 1/2 3/2 [52 5/2 1] 4 [6 5/2 [52 2] 3] 5/2 /2 [50 1] [65 1/2 2] [64 5] 82 11 ] ] 2] 00 514 40 /2 [4 9/2 [ [ 2 1 3/ 3/2 2[ 40 ] 4] 32 7/ 2d3/21h11/2 1] [65 3/2 [5 6.0 1/2 7/2[523] ] 0] 30 [5 /2 [66 1 3s1/2 − ω) Es.p. (h 1/2[411] 2] 5/2 [40 5/2[413] 1/2[411] 1g7/2 3/2 [411] 1/2 1] 2] [42 [54 53 1/2 0] 2[ 0] 5/ [55 5.5 3/2 [66 1/2 2d5/2 1] 43 2[ 1/ 2] 3/2 [54 [4 20 1/2[301] 5/2[303] 1] 1/2 ] 50 5/2[532] ] 01 3 2[ 1/ 9/ 2[ 40 4] 1/2[541] 3/2[301] 413] 7/2 [ 3/2 [30 [54 ] 3/2 [43 01 [3 0] 4 [4 0] [55 2 1/ 1] 1] 3/2 1/2 422] 1/2 1g9/2 5.0 1] 5/2 [ −.3 −.2 −.1 .0 .1 .2 .3 .4 ε2 Figure 5. Nilsson diagram for neutrons, 50 ≤ N ≤ 82 (ε4 = ε22 /6). .5 .6 1/2[640] 1/2[400] 3/2 [5 21] 5/2 0] 0] 53 ] 02 ] 2[ 3/ 11 /2 [5 05 ] 660 2d3/21h11/2 2] 53 1/2 [ 6.0 761] ] 651 3 1/2[880] ] 42 [6 5/2 70] 1/ 2 [7 ] 651 1/2 [ [ 3/2 ] 00 ] 02 [4 [4 1/2 2 / [4 3/2 [ 2 5/ 4 40 2[ 7/ 3/2[521] 1/2[640] ] 42 [6 [66 [ 1/2 82 61] 1/2 [7 1] [65 3/2 1/2 1] [54 1/2 2] 40 ] 2 [ 400 / 3 [ 2 1/ 4] [51 2 / 9 ] 7/2[523] 1/2[411] 3s1/2 1] 1/2 [41 1/2 [411] ] 1g7/2 3/2[411] 1/2[530] 1/2 [7 ] 3/2 3/2 [411 70] − ω) Es.p. (h 651 1/2 [ 13] 5/2 [4 02] [4 5/2 1] [65 3/2 [54 [42 0] 3/2 [55 5.5 2] 5/2 [5 32 ] [4 [4 20 1/2 [6 1/2 1/2 1] 1/2 2d5/2 ] 31 ] 60] 50 9/ 2[ 40 4] 1/2[301] 3] 30 3] 1/2 [ [ 5/2 660] 41 7/2 [ 3 3/2 ] 01 [3 3/2 1/2 22] 0] [55 5/2 [4 [43 [54 3/2 1/2[541] 1] 30 /2 [ 1/2 1g9/2 5.0 ] 1 [30 1/2[420] 1] 0] 44 2[ 1/ 1] −.3 −.2 −.1 .0 .1 .2 .3 .4 ε2 Figure 6. Nilsson diagram for neutrons, 50 ≤ N ≤ 82 (ε4 = − ε22 /6). .5 .6 1/2[750] 5/2[503] 1/2[501] 1/2[770] 1] [50 9/2[734] 5/2 [62 2] 761 3/2 22] 1/ 2 [ ] 1] 5/2 63 2] 3] 74 64 2[ 1/ 2[ 7/ 2[ 3/ 2] 75 5/2 [6 7/2 [ ] [ 5/2 1 [76 50 3] 3/2 2g9/2 2 [86 126 ] [ 3/2 1] 50 1/ 2[ 5 3 /2 [ 06] /2 [5 503 01 ] ] 2 [6 2] 13/ ] 33 [6 [7 5 1/2[510] 512] 3/2 [ 10] 5 1/2 [ ] 761 ] 15 2 1/ ] 752 /2 [871] 3 7/2 2 5/ 5 /2 [ 3/2 2f5/2 880] 1/2 [ ] 43 [7 0] [77 1/2 1] [65 7.0 1/2 3p1/2 [6 1 1/2[750] 1/2[631] ] 1] [76 [770 1] 63 3/2 1/2 3p3/2 2[ 3/ ] 3/2 [512 1/2[510] 3] [50 [50 1/2[880] 5/2[512] 7/2 9/2 1i13/2 ] [514 ] [512 2] [75 5/2 761] 1/2 [ 7/2 5/2 − ω) Es.p. (h 5] 9/2 [624] 2 2 [ [40 40 2 0] ] 1/ 3/ 0] ] 3/2 42 1] [64 [52 0] [64 7/2[404] 40 2] 0] [53 1] 2] 1/2 3/2 1/2 2f7/2 1] [6 [65 523] 6.5 3] [52 5/2 3/2 5/2 [ [63 [64 1/2 1/2 7/2 1h9/2 2[ 1/2 [52 3/ 1] 2[ 5/ 1/ 2 ] ] 660 [4 00 ] 770 [ 1/2 2] 40 2] 1/2 [ 53 1] 54 2[ 3/ [ 1/2 7/2[633] 1/2 5/ 2 50 4] 11 40 0] 40 7/ 2[ /2 [ 2[ 2] 1/ ] [64 1 [65 5/2 [51 1] [65 6.0 −.3 4] 9/2 3/2 3 1/2 5] [4 02 ] 0] [66 2] 40 [ /2 −.2 −.1 .0 .1 .2 .3 .4 ε2 Figure 7. Nilsson diagram for neutrons, 82 ≤ N ≤ 126 (ε4 = ε22 /6). .5 .6 5/2[503] ] 01 [5 3/2 5 3/ /2 [ 60 2 [50 503 6] 1] ] /2 [ 3] 50 ] 13 31 1] [5 7/2 9/2 2] [51 [51 1/2 [990 [5 03 05 ] ] 5/2 2] ] [63 3] 1/2[521] 2] 0] [64 [53 1] 1/2[400] 3/2 1/2 [52 0] 40 61] ] 32 1] [54 [5 1/2 [7 2 3/ 1/2 1/ 1/2 2] 40 ] 2 [ 400 / 3 2[ 1/ ] 0 [66 9/2 4] [51 ] 02 5/ 40 [50 5] .4 ε2 Figure 8. Nilsson diagram for neutrons, 82 ≤ N ≤ 126 (ε4 = − ε22 /6). 761] .3 1/2[880] 2] [64 5/2 70] 1/2 [7 1] .2 ] [65 660] 1/2 [ .1 651 40 2[ 5/ 1/2 [ 3/2 2] 3/2 [ 4 2[ 4] 2[ 2] 0] 40 40 2 [ 1/2 [ / 3 3/2[521] 1/2[640] 7/ 11 /2 71] 2] 1] 3/ 521] 2[ .0 2] 40 2[ 1/2 [ 64 [65 2[ 5/ 3/2 ] 2] 0] 1] 3/2 [75 1/2 [88 [52 3/2 [8 5/2 ] 70] 761 1/2 [7 1/2 5/2 [523 3/2[752] 1] 63 61] [51 5/2 1/2 [87 2[ 3/ 1/2 [7 4] 7/2 1h9/2 −.1 [6 1] 0] [51 11 7/2 −.2 1/2 63 2[ 1/ 1/2 3] 871] 5] 1 [6 74 3/2 [ 1 3/2 [ − ω) Es.p. (h 7/ 2[ 1/2[501] 1/2[770] [5 01 ] 1/ 2 2] 761] 1/2 [ 0] 1 /2 [5 ] 24] 6.0 −.3 0] [75 1] ] 2[ 512 9/2 [6 2f7/2 2] [86 5/2 1/2 [871] 3/2 1] 2] 63 [75 2[ [76 ] 0 [64 [770 1/2[510] [ 3/2 /2 3/2[981] 3/2[512] 7/ 3p3/2 6.5 0 1/2 [10 1 ] 3] 12] 3/2 [5 ] 0 1/2 [51 1i13/2 1/2 [990 ] [63 5/2 3/ 3/2 1/2 2f5/2 [750 ] 31 [6 5/2 1/2 7.0 3] 2 1/ 2] ] 2] 51 64 /2 [6 1 3p1/2 74 1/2 [75 ] 2[ 3/ 126 2[ 5/2 1 [76 7/ 80] 1/2 [8 3/2 2g9/2 .5 .6 11/2[835] 9/2[604] 1/2[981] 7/2[723] 3/2[862] 5/2[602] 7/2[604] 3/2[602] 1/2[600] 1/2[750] 9/2[725] 1/2[880] 3/2[871] 7/2[853] 1/ 2] [60 0] [60 1/2 3] 07] [50 2 [7 1] 7/2 [60 4] 1/2 15/ ] 4] 84 2[ 16 [7 ] 04 [6 9/2 [50 [503 1] ] 3/2 /2 13 6] ] ] [862 /2 [860 1 3] 50 2[ 5/ ] 15 [6 0] 1/2[981] 3/2[981] 1/2 9/2 622] [62 5/2[503] 7/2[613] 3/2[501] 3/2 60 9/ 1] 1] /2 [ ] [74 [87 11 1 [85 871] 3/2 3/2 ] 613 3/2 [ 1] 622] 9/2[505] 1] 7/2 [ [74 9/2 [ 3/2 [ [50 1/2 1] ] 05 [5 [73 4] 3] [50 0] 7/2 ] ] 9/2 9/2 [50 13/ 3/2 [75 1] 633 1/2 [76 761 1/2 [ 3/2 1] 2 [6 [50 06] 1] 2] 1/2 1/2[620] 7/2[853] 5/2[743] [74 ] [86 7/2 [624] 52 5/2 [ 3/2 [7 5/2 5/2 5/2 [6 22] ] /2 11 15 [6 5/2 [62 3] 2] 1/2[990] 1/2[871] 1] 5/2 63 2[ 2] 74 2[ 7/ 1/ 64 2[ 2] [86 43 ] 1] 50 2[ 5/ 3/2 2 [5 [5 03] 01 ] 2] ] [75 3/2 [871 [7 880] 1/2 [ ] 7/2 31 [6 0] [64 0] [77 1/ 3/2 3/2 1/2 1/2 1/2 5/2 2] .2 .3 1] [76 .1 1/2[510] [75 3/2 ] 1 [65 .0 ] 1/2 [ 2] 1/2 3/ −.1 0 10 0 2] 1] [75 − ω) Es.p. (h 1/2 [1 3/2 4] 126 −.2 9/2[615] 84 [74 3] 74 1] 3/2 [76 5] [72 7.5 7.0 −.3 5/2[853] 5/2[732] 1i11/2 3p1/2 3/2[972] 5/2[972] 1/2[851] 2[ 90] 73 1/2 2[ 1/2 11/2 9/ 1/2 [9 2[ 5/ [61 5/ 1] 3/2 [61 734] 2g9/2 73 5/2 3/2 970] [85 1] ] 1j15/2 2] 0] 13 [6 5/2 3d5/2 3/2[611] 73 2[ 1] 2 60 2g7/2 1/2 [ 7 /2 1/ 3/2 2[ 5/ 3] 85 4] 1/2[611] ] 8.0 5/2[613] 1] 84 2[ [87 4s1/2 2] 3/ 3/2 3d3/2 73 [ 85 2h11/2 1/2[611] 2[ 3/2 7/2[734] 3/ 860] 2[ 0] 1/2 [ 2] 86 9/ 73 [ 5/2 [ 5/2 ] 871 1/2 [ 2[ 512] 3/2 [ .4 ε2 Figure 9. Nilsson diagram for neutrons, N ≥ 126 (ε4 = ε22 /6). .5 .6 60 2] 0] 1/2 9/2[604] 6] 60 /2 [ 1] 50 13 7/2 1] 1/ 3] 3] [85 50 ] 16 [7 /2 2[ 4] [60 7/2 13 ] [74 862 3/2 3] 3/2 [ [85 07] [6 2[ 5/ 3/2[622] 3/2 [622] 2[ 3/ 9 0] 1] 11 /2 [ 60 ] /2 3/2 [622] [62 91]] [10091 1/ 3/22[1 ] 13 2 7/ 7/2 2 [7 3/2[972] 1/2[970] 3/2[851] 2] 871 [86 3/2 [ 5/2 1] 6] 9/2[844] [6 72 2] 15/ ] 15 2 9/ 11 ] [75 [76 1/2 4] 0 [6 9/2[615] 5/2[853] 5] /2 [ 3] 880 3/2 1/2 − ω) Es.p. (h 3/2[732] 72] 74 1/2 [ 11] 3/2 [6 1/2[730] 50 3/2 [ [60 1] 2[ [ 11 [6 5/2 [9 1/2 [98 0 0] 1/2 [10 1 1] 71] 5/ 3 61 ] 3/2 0] 1/2 [8 1/2 [99 [61 ] 3d5/2 2] [85 2] 750] 1/2 [ 1] 3/2 02 2g7/2 [73 1/2 73 1] [85 3/2 2[ 1] 74 [61 [6 2 5/ 3] [61 3/2 71] 1/2 [8 5/ 1] ] 1/2 [611 2 5/ 5/2 ] 3] 5/2 ] 8.0 30 [ 1/2 [87 4s1/2 3/2[981] 1/2[730] 5/2[602] 3/2[862] 7/2[604] 3/2[602] 1/2[600] 1/2[880] 7/2[853] 9/2[725] 4] 3/ 2 3d3/2 [7 60] [84 7/2 [734] 2h11/2 1/2 1/2 [8 3 2] [86 1] 5/2 /2 [87 9/2 1/2 [620] 1/2 [620] 9/2 [734 ] 7/2 [613] 5/2[743] 1/2[741] 1j15/2 3] 50 1] 2[ 5/ 50 2[ 3/ ] 01 [5 5/2 [622] 50 3] 2[ 7/ 1] ] 1/2 [10 1 [5 0 1] 1] 3/2 1/2 [98 1/2 [990 80] 63 2[ ] 1] 05 [5 50 1/ 2[ 9/2 1/2[510] 3] [5 0 7/2 3] ] 5 3/ /2 [5 2 [ 03 50 ] 1] 74 31 [6 1/2 0] [51 1/2 .3 2[ ] 31 [6 .2 3/2 7/ 2 1/ .1 761] 11 2] 2] [75 71] 3/2 [8 3/2[512] 1/2 [ /2 [6 3/2[981] [86 3/2 3] [ ] 15 0 0] 5/2 [63 1/2 .0 1/ 5/2 2] [75 5/2 1] 63 ] 2[ 3/ /2 [761 ] 3 770 −.1 ] [750 1/2 [8 1] −.2 1/2 2] 0] ] 2] 51 64 /2 [6 1 3p1/2 3/2[741] [75 [76 [64 2[ 3/ 126 3/2[862] 1/2[620] 1/2 3] 2] 1] 5/2 3/2 1/2 2g9/2 74 [62 860] [74 2[ 71] 7/ 5/2 7.0 −.3 1/2 [8 7.5 1/2 [ ] 624 7/2 [ 3/2 1i11/2 2] [51 1/2 9/2[624] 0] [51 .4 ε2 Figure 10. Nilsson diagram for neutrons, N ≥ 126 (ε4 = − ε22 /6). .5 .6 3/2[402] 5/2 2[ 1/ 3] 3] 0 4 2[ 5/ 11 /2 ] [50 5] 1 [65 3s1/2 [63 2] 1/ 2 [4 7/2 ] 42 [6 1] ] [65 660 3/2 1/2 [ ] 00 2 1/ 5/2 6.0 [52 2 5/ 82 1/2[640] ] 2] ] 0 40 2 [64 1] 3/2 /2 [76 3 53 0] 2[ 7/2[404] [77 ] 51 [6 3 /2 6 6 0 ] [ ] 1 /2 3/ [52 7/2 [ 63 1] 3 1/2 3/2 4] 40 2] 5/ 7/ 2[ ] 40 30 2[ 2] [51 [5 9/2 4 [6 1/2 4] 2d3/2 1/2 [411] 7/2 [52 1h11/2 − ω) Es.p. (h 1/2[411] 3] 3/2[411] 2d5/2 [54 ] 20 1] 50 [4 ] 0] 1/2 [5 1/2 1/2 [42 2] 5.5 3/2[651] [66 3/2 1/2 1g7/2 3/2 [411] 5/2 [413] 1/2 5/ ] 31 [4 2[ 53 2] 1/2[301] 3/2 [5 5/2[303] ] 41 50 ] 01 5/2 [3 [53 2] 2[ 40 4] 1/2 1/2[541] 9/ ] 3/2 01 [3 13] 7/2 [4 1] 3/2 .1 .2 .3 1] .0 [54 −.1 3/2 −.2 5/2 [4 22] 3/2 [43 1] 0] [55 −.3 1g9/2 1] [30 3] [30 5/2 1/2 5.0 1/2 [30 .4 ε2 Figure 11. Nilsson diagram for protons, 50 ≤ Z ≤ 82 (ε4 = ε22 /6). .5 .6 3/2[642] 7/2[633] 3/2[521] 3/2[402] 1/2 [7 5/2 [5 23] 2[ 53 1/2[640] ] 2[ 5/ 1] [54 64 82 3/2[521] 0] 40 2[ 1/ 651 1/2 [ 1/2 2] 61] 1] ] [65 [660 3/2 1/2 3/ 2] 2] 0 5/2 [4 3/2 0] [7 6 40 ] 2] [5 05 1] 64 2[ 1/2 11 /2 3s1/2 6.0 770] 1/2 [ 5/ [ 1/2 2 1/2 [411] 0] 4] [4 0 [4 1/2 [411] 1] 7/2[523] − ω) Es.p. (h 1h11/2 3/2 [4 11] 1] 3/2 [41 ] 13 5/2 [4 2d5/2 5/2 [53 2] 1] 1/2 [ 660 ] 0] ] 41 20 [5 [4 [55 5.5 1/2 3/2 2] 1/2 [42 [65 3/2 3/2 1g7/2 1] [65 [65 3/2 1/2 [411] 1/2 7/ [66 ] 02 2 5/ ] 30 [5 [51 9/2 1/2 4] 2d3/2 ] 1/2 1] [43 1/2[301] 50 1/2 2[ 40 0] 4] [42 [30 1/2 9/ 1] 1] [54 1/2 1] ] 5/2 [4 22] 3 [43 −.2 −.1 .0 1] 1] −.3 1/2[660] 1] 30 /2 [ [54 3/2 1] [30 3] 1/2 [30 2 / 5 [30 3/2 1g9/2 0] [55 5.0 3/2 1/2 413 7/2 [ .1 .2 .3 .4 ε2 Figure 12. Nilsson diagram for protons, 50 ≤ Z ≤ 82 (ε4 = − ε22 /6). .5 .6 1/2[770] 3/2[761] 3] 74 9/2[734] 0 [75 [86 ] 2] 1/2 0] 3/2 [88 1 [87 ] ] 31 [6 3/2 3] 74 2[ 7/ 3] 63 [ 50 1/2 7/2 3/2[752] ] 2] [64 3/2 0] 0 [64 ] 761 1/2 [ 2[ 3] 5/ 1] 52 [ 1/2 1/2 114 13/ 2 [6 06] [77 5] 512] 5/2 [ 7/2[514] 5] 61 9/2 11 [50 [ /2 512] 5/2 [ 9/2[624] 2] 40 2[ 1/ 3/ 2] [75 ] 5/2 [640 1/2 [63 0] 2] 3] [52 40 1] [5 21 ] [76 1] 7/2[404] 1] [65 0] [77 3/2 1/2 1/2 2] 64 1/ 2[ 1/2 2[ 5/ 1h9/2 7/2 [64 3/2 3/2 6.5 4] [51 1] 7/2 [65 1i13/2 2[ 40 0] 2f7/2 7/2[743] 1/2 − ω) Es.p. (h 5/2 2] 3/2 [51 3/2[512] 2f5/2 7.0 0] 1/2 [51 1 /2 510] 1] [63 3] 1/2 2] 2[ 1/2 [ 3/2[512] [50 5/2 [ 5 [7 7/ 7/2 3/2[501] 50 3] 2] [75 3/2 5/2 3p3/2 1/2[510] 7/2[624] 2] 53 1] [65 660] 3/2 1/2 [ 2[ 3/ 1/2 5/2 1 [54 [52 3] ] 7/ 2[ 63 1] [65 660] [ 1/2 [4 3] 5/2 3/2 ] 00 4 2[ 02 ] 82 1/ 2] 50 5 ] 40 .0 .1 ] 04 [4 2] 40 .2 7/2 2[ 5/ −.1 2] [51 0] −.2 [53 9/2 [64 1/2 4] 2d3/2 −.3 5/2 3s1/2 6.0 11 /2 [ 2[ 3/ .3 .4 ε2 Figure 13. Nilsson diagram for protons, Z ≥ 82 (ε4 = ε22 /6). .5 .6 [5 0 5/2 ] 3/2 750 1 /2 [ ] 1] 33 0] ] ] 880] [64 [6 2 [86 3 [6 1/2 [ 5/2 ] 631 5/2 3/2 3/2[512] 1/2 7.0 2] [51 [ 1/2 1/2 [5 10] 2f5/2 3/2[512] 7/2[503] 3/2[871] 1/2[770] 3/2[761] 3/2[501] 3] ] 52 [7 5/2 42] [6 43 ] 510 1/2 [ ] 31 [6 [7 3/2 3p3/2 2 3/ 7/2 [ 1/2 7/ 74 3] 7/2 ] [752 3/2 [50 3] 1] 52 2[ 06] 2 [6 13/ 9/2 11 /2 [50 [6 5] 15 ] ] [75 2] − ω) Es.p. (h 5/2 1/2 [990 871] 3/2 [ 61] 1/2 [7 24] 512 5/2 [ ] 14 2 [5 1/2 7/ 1i13/2 1/2[400] 3/2[402] [52 1] 1/ 2[ 1/2 [ 6.5 [63 1] 3] 40 1] 2] 80] [64 0 [64 1/2 2] [52 1/2 [8 [ 1/2 64 1h9/2 3/2[871] 0] 3/2 2[ 5/ 3/2 52 651] 7/2 7/2[514] 7/2[743] 9/2 [6 ] 2f7/2 ] 512 [ 5/2 1] [76 3/2 0] [77 1/2 114 ] 5/2 [5 3/2[521] 2[ 40 1/ 651] 1] [54 1/2 [ 1/2 0] 1] 1/2 [76 2] 53 1] [65 60] 3/2 1/2 [6 2[ 3/ 23] 82 2] 40 2[ 5/ 3/2 [ ] 7/ 5] 11 /2 [ 50 ] 0] 7 1/2 [7 ] 1/2 2] 40 5/ 2[ .2 .3 1/2 [411] 1] [65 .1 0] [53 .0 3/2 −.1 [51 0] [66 −.2 9/2 1/2 4] 2d3/2 −.3 42 3s1/2 6.0 [6 2] 40 2[ 3/ 5/2 2[ 40 4] [4 761 00 2 1/ 1/2 [411] .4 ε2 Figure 14. Nilsson diagram for protons, Z ≥ 82 (ε4 = − ε22 /6). .5 .6 Additional quantities of interest for describing a rotational band include the rotational frequency E γ((J +2)→J ) + E γ(J →(J −2)) − h ω(J ) = h hhhhhhhhhhhhhhhhhhhhhhhhh MeV , 4 (18) 2J − 1 _ J 1(J ) = hhhhhhhhhhhhh − h 2 MeV −1, E γ(J →(J −2)) (19) 4 _ J 2(J ) = h hhhhhhhhhhhhhhhhhhhhhhhhh − h 2 MeV −1 . E γ((J +2)→J ) − E γ(J →(J −2)) (20) the kinetic moment of inertia and the dynamic moment of inertia An experimental Routhian plot is often prepared to compare rotational bands with theory. This plot is restricted to sequences with ∆J =2 when defining a band. The frequency parameter ω(J ) is defined as E (J +1) − E (J −1) ω(J ) = hhhhhhhhhhhhhhhhh , Jx (J +1) − Jx (J −1) (21) where the x-component of angular momentum Jx is Jx (J ) = √ddddddddddd (J +1/2)2−K 2. (22) E ′(J ) = 1/2 [E (J +1)+E (J −1)] − ω(J )Jx (J ). (23) The experimental Routhian13 is defined by These Routhians are normally referenced to even-even nuclei where the quantities e ′(ω) = E ′(ω)−Eg′ (ω) , (24) j (ω) = Jx (ω)−Jxg (ω) . Here Eg′ (ω) and Jxg (ω) are the Routhian and the x-component of the angular momentum of the reference configuration, respectively. For an odd-A nucleus, the Routhian becomes e ′(A ,ω) = E ′(A ,ω) + ∆ − 1/2 [Eg′ (A +1,ω) + Eg′ (A −1,ω)], (25) where A is the mass number and ∆ is the average even-odd mass difference. 4. Signature Splitting The lowest energy state of each single-particle Nilsson configuration will have J =K =Ω (Ω≠1/2). For each configuration there is a rotational band of levels where K =Ω and the energies are given by equation 4 with J taking on the values K , K +1, K +2, K +3, . . . Coriolis and centrifugal forces introduce an additional term to the matrix element which involves a phase factor σ=(−1)J +K called the signature. This term alternates sign for successive values of J and implies that rotational bands with K ≠0 divide into two families distinguished from each other by the quantum number σ. Bengtsson and Frauendorf13 have redefined the signature quantity for single particle states as α=±1/2, where α is an additive quantity where r =e −i πα. The total signature αt for a configuration restricts the angular momentum to J = αt mod 2 , (26) determining whether the band has odd or even particle number N , where N = 2αt mod 2 . (27) For even-A nuclei, we obtain the 2-quasiparticle sequences: if αt = 0 (r = +1), J = 0, 2, 4, 6, . . . , if αt = ±1 (r = −1), J = 1, 3, 5, 7, . . . . hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh 13 R. Bengtsson and S. Frauendorf, Nucl. Phys. A327, 139 (1979). (28) Similarly, for odd-A nuclei: if αt = +1/2 (r = −i ), if αt = −1/2 (r = +i ), J = 1/2, 5/2, 9/2, . . . , (29) J = 3/2, 7/2, 11/2, . . . . An example of signature splitting is shown in Figure 15. Collective particle configurations can also be discussed in terms of the alignment of the particle’s intrinsic angular momentum with the angular momentum of the core. The "favored" (lowest energy) configuration occurs when these momenta are aligned to the maximum value. Decreasing the alignment − produces the "unfavored" configuration. These two configurations are analogous to the signature by 1h partners described above. In octupole deformed nuclei, rotational states may be characterized by eigenvalues s of the simplex operator14 J=PR−1 where R corresponds to reflection by 180° about an axis perpendicular to the symmetry axis and P is the parity operator. The spin J and parity p of a state in a rotational band which can be described by this "reflection" symmetry are related by p =e −i πJ . Accordingly, s =±1 for even particle number (integral J ), and s =±i for odd particle number (half-integral J ). These reflection-asymmetric deformations (octupole-quadrupole deformed) lead to bands of alternating parity, connected by enhanced E 1 transitions, with levels nearly degenerate in energy for the same spin but opposite parity (parity doublets). Examples of parity doublets for an odd-particle system (221Ra)15 and an even-particle system (224Ac)16 are shown in Figure 16. 5. Superdeformation and Hyperdeformation In 1968, Strutinski17 predicted a second minimum in the potential well for a deformed nucleus. This phenomenon was subsequently identified with fission isomers in the actinides, first observed by Polikanov et al.18 The associated shell gaps, calculated with an axially symmetric harmonic oscillator potential by Nix19 and by Bohr and Mottelson20, are shown in Figure 17. These gaps occur with varying magic numbers for ratios of the semi-major to semi-minor axis of 3/2 and 2 (superdeformation), and 3 (hyperdeformation). In 1986, Twin et al 21,22 reported the first evidence, for a superdeformed band in 152Dy. Six superdeformed bands have been found in 152Dy and are shown in Figure 18. Tentative evidence for a hyperdeformation in 152Dy was reported by Galindo-Uribarri et al 23 who observed a δE γ=±30 keV ridge structure in coincidence data for 152Dy. Discrete transitions, possibly from a hyperdeformed band in 153Dy, were reported by Viesti et al 24. hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh 14 W. Nazarewicz, P. Olanders, I. Ragnarsson, J. Dudek, and G.A. Leander, Phys. Rev. Lett. 52, 1272 (1984). 15 J. Fernández-Niello, C. Mittag, F. Riess, E. Ruchowska, and M. Stallknecht, Nucl. Phys. A531, 164 (1991). 16 P.C. Sood, D.M. Headly, R.K. Sheline, and R.W. Hoff, At. Data Nucl. Data Tables 58, 167 (1994). 17 V.M. Strutinski, Nucl. Phys. A95, 420 (1967); ibid A122, 1 (1968). 18 S.M. Polikanov, V.A. Druin, V.A. Karnaukhov, V.L. Mikheev, A.A. Pleve, N.K. Skobelev, G.M. Ter-Akopyan, and V.A. Fomichev, Zhur. Ekspti. i Teoret. Fiz. 42, 1464 (1962); Soviet Phys. JETP 15, 1016 (1962). 19 J.R. Nix, Ann. Rev. Nucl. Sci. 22, 65 (1972). 20 A. Bohr and B.R. Mottelson, Nuclear Structure, Vol. II, p. 591, Benjamin, New York (1975). 21 P.J. Twin, B.M. Nyako, A.H. Nelson, J. Simpson, M.A. Bentley, H.W. Cranmer-Gordon, P.D. Forsyth, D. Howe, A.R. Mokhtar, J.D. Morrison, J.F. Sharpey-Shafer, and G. Sletten, Phys. Rev. Lett. 57, 811 (1986). 22 P.J. Dagnall, C.W. Beausang, P.J. Twin, M.A. Bentley, F.A. Beck, Th. Byrski, S. Clarke, D. Curien, G. Duchene, G. de France, P.D. Forsyth, B. Haas, J.C. Lisle, E.S. Paul, J. Simpson, J. Styczen, J.P. Vivien, J.N. Wilson, and K. Zuber, Phys. Lett. B335, 313 (1994). 23 A. Galindo-Uribarri, H.R. Andrews, G.C. Ball, T.E. Drake, V.P. Janzen, J.A. Kuehner, S.M. Mullins, L. Persson, D. Prevost, D.C. Radford, J.C. Waddington, D. Ward, and R. Wyss, Phys. Rev. Lett. 71, 231 (1993). 24 G. Viesti, M. Lunardon, D. Bazzacco, R. Burch, D. Fabris, S. Lunardi, N.H. Medina, G. Nebbia, C. Rossi-Alvarez, G. de Angelis, M. De Poli, E. Fioretto, G. Prete, J. Rico, P. Spolaore, G. Vedovato, A. Brondi, G. La Rana, R. Moro, and E. Vardaci, Phys. Rev. C51, 2385 (1995). 923 839 776 (53/2+) 5225 (49/2+) 830 782 6007 7/2– 698 630 810 787 772 739 716 584 533 510 678 651 2973.5 2231.6 (33/2+) 1722.4 (29/2+) 1245.2 (25/2+) 821.9 (21/2+) 2261.9 (31/2+) 1683.7 (27/2+) 1187.0 (23/2+) 778.8 (19/2+) 465.1 15/2+ 247.3 120.346 69.219 11/2+ 7/2+ 607 515 (35/2+) 2746.1 578 566 517 492 479 2913.2 2295.1 523 497 477 428 408 423 448 393 1688.4 1165.3 326* 314 355 1034.0 737.2 83.965 190.02 5/2– 0 5/2[523] α=-1/2 5/2[642] α=+1/2 5/2[523] α=+1/2 163 68Er Figure 15. Signature splitting observed in 163Er. 213 9/2– 13/2+ 9/2+ 5/2+ 108 17/2+ 127 467.2 13/2– 320.2 218 640.8 277 321 236* (37/2+) 1482.1 (17/2–) (11/2)– 3712 1960.8 (21/2–) (15/2)– (39/2+) 2452.7 (25/2–) (19/2–) 3629.5 3279 2969.7 (29/2–) (23/2–) 4499 3535.8 (33/2–) (27/2–) (43/2+) 4402 3863.6 (41/2+) (37/2–) (31/2–) 5309 5213 4165.3 (41/2–) (35/2–) (47/2+) 811 714 648 4511.2 (45/2+) (39/2–) 6042 4863 (45/2–) (43/2–) 6923 5639 (49/2–) (47/2–) (57/2+) 6478 (53/2–) (51/2–) 6853 880 7373 (57/2–) (55/2–) 7757 846 (59/2–) 895 904 8296 412.2 199.3 91.552 5/2[642] α=-1/2 (13/2+) 253.5 5+ 177.0 711.6 4– 566.0 3– 438.0 341.5 210.9 2– 1– 0– 50 849.6 4+ 130.4 116.7 78.4 3+ 37.2 2+ 1+ 0+ 17.2 0 221 88Ra 29 350 176 314 331 195 155 (11/2+) 6+ 80.5 22 (13/2–) 184.2 41 61 318.9 5– 38 440.4 (15/2+) 237.2 37 (17/2–) 284 573.1 274 (19/2+) 128 225 688.4 146 (21/2–) 6– 1180.5 1025.9 138 (23/2+) 866.9 1375.7 17 122 (17/2+) (25/2–) 97 302 294 115 248 133 254 (19/2–) 990.4 (27/2+) 131 354 147 179 (23/2–) (15/2–) 1197.4 124 (25/2+) (21/2+) 1344.4 207 331 (27/2–) 51.9 29.8 22.0 224 89Ac Figure 16. Examples of parity doublets arising from reflection asymmetry in 221Ra and 224Ac. 8 7 8 168 190 182 140 140 7 112 110 100 6 80 70 68 ⁄ − ENERGY IN UNITS OF hω 6 60 5 4 5 40 44 40 28 26 4 20 16 14 3 8 3 10 6 4 2 1:2 2 2 2 2 2:3 1:1 3:2 2:1 1 –1.0 3:1 1 – 0.5 0 ω⊥ − ω 3 δosc = − ω 0.5 1.0 Figure 17. Single-particle level energies calculated for an axially symmetric harmonic oscillator (from reference 18). 1546 19393.7+x 1376 (24+) x SD-1 band (36) (40) 825.9+y (38) y (36) (34) SD-2 band 1632.7+z 793.0+z (29–) z (27–) SD-3 band 954 1434 1388 1344 1300 1257 1212 1123 1031 5589.0+v (36–) 2988.4+u (34–) 2163.4+u (32–) 1390.6+u (30–) 669.6+u (28–) u (26–) SD-4 band 152 66Dy Figure 18. Superdeformed rotational bands for 152Dy 3733.9+v (40–) 2882.8+v (38–) 5237.9+w 4251.8+w 895 3865.2+u 941 4635.2+v 7346.5+w 6269.2+w 850 (38–) 901 (44–) 4794.2+u 9636.3+w 8469.2+w 986 (40–) 12104.6+w 10847.9+w 1077 1105 1055 1005 6594.1+v 14748.8+w 13404.5+w 1167 1304 1206 1156 1228 1180 1131 (31–) (42–) 17570.7+w 16137.2+w 3310.6+w 2415.7+w 2084.0+v 1337.0+v SD-5 band 805 (33–) 1681.3+y 6802.7+u 747 2523.9+z 7649.1+v (42–) 877 (35–) (44–) (46–) 825 3468.7+z 8754.1+v (48–) 5772.9+u 773 (42) 7883.5+u 929 998 945 (44) (46–) (50–) 4466.9+z (37–) (54–) (36–) 642.1+v (34–) v (32–) 762 602.4+x 2576.5+y (46) 9014.1+u 5519.3+z (39–) (56–) (52–) 851 (48) (41–) (58–) 9909.9+v 799 6624.2+z (43–) 12369.5+v 11115.7+v 695 (50) 7781.1+z (45–) 1081 (52) 8989.0+z (47–) 721 (38) 1249.9+x 3508.7+y 10194.4+u 1030 1208 (54) 891 970 932 895 (40) 4478.6+y 1254 1328 1281 1369 1314 1260 (49–) 13673.7+v 642 1009 5487.1+y 11422.4+u (48–) 840 648 (42) 1942.6+x 602 (28+) 6536.3+y 855 693 2680.7+x (30+) (26+) 3464.7+x (44) 826 784 4294.6+x 738 (34+) (32+) (46) 10249.4+z 9949.9+y 7628.9+y (51–) 5171.0+x 830 (38+) (36+) (48) 6094.2+x 876 (40+) 7064.4+x 923 (42+) 1049 970 (50) 11563.2+z 979 8081.8+x 12703.4+u (50–) (56) 8766.5+y (53–) (52–) 793 (44+) 1017 (52) 12931.8+z 12458.2+y 1157 9146.7+x (60) 11180.5+y 1093 (46+) 14031.1+u (54–) (58) 1138 1065 (54) (55–) 1105 10259.4+x 14357.6+z 1052 (56) 15407.0+u (60–) 1426 1377 1327 (58) (57–) 13785.6+y 1278 (60) (62–) 15840.3+z 15162.7+y (62) 1231 11419.9+x (62) (64–) 17384.4+z 16586.3+y 1183 1305 12628.5+x 1113 (50+) (48+) 13885.1+x 1161 (52+) 15189.9+x 1209 (54+) (64) (64) 1257 (56+) 16542.8+x 1424 1353 (66) (58+) 18989.1+z 18063.4+y 1544 (66) 1483 17944.1+x 1477 (60+) 1401 (68) 670 (62+) 1605 20891.5+x 1450 (64+) 22437.1+x 1498 (66+) 1566.0+w 761.5+w w SD-6 band
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