ADOPTED LEVELS, GAMMAS for 251Es
Authors: E. Browne, J. K. Tuli | Citation: Nucl. Data Sheets 114, 1041 (2013) | Cutoff date: 1-Jan-2012
Full ENSDF file | Adopted Levels (PDF version)
| Q(β-)=-1440 keV 16 | S(n)= 6785 keV SY | S(p)= 3947 keV 6 | Q(α)= 6598 keV 3 | ||
| Reference: 2012WA38 |
| References: | |||
| A | 251Fm ε decay | B | 255Md α decay |
| C | 250Cf(α,t) | ||
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) | E(γ) (keV) | I(γ) | M(γ) | Final Levels | |
| 0 | C | 3/2- | 33 h 1 % ε = 99.5 2 % α = 0.5 2 | |||||
| 8.4 10 | AB | (7/2+) | 8.3S | | 0 | 3/2- | ||
| 31.7 10 | ABC | 5/2- | ||||||
| 55.8 10 | AB | (9/2+) | 47.48 6 | | M1+E2 | 8.4 | (7/2+) | |
| 76.2 11 | A C | 7/2- | ||||||
| 114.1 10 | A | (11/2+) | ||||||
| 182.5 10 | A C | (13/2+) | ||||||
| 263.0 11 | A | (15/2+) | ||||||
| 411 2 | C | (1/2-) | ||||||
| 452 2 | C | (5/2-) | ||||||
| 461.5 10 | AB | 7/2- | 385.3 2 405.6 1 429.7 1 453.1 1 | 2.1 2 68 4 5.7 5 100 6 | (M1) (E1+M2) M1+E2 (E1+M2) | 76.2 55.8 31.7 8.4 | 7/2- (9/2+) 5/2- (7/2+) | |
| 515.5? | B | |||||||
| 523.9 10 | BC | (9/2-) | ||||||
| 548 2 | C | (7/2-,9/2-) | ||||||
| 661 3 | C | (1/2+) | ||||||
| 778.0 10 | A | (9/2+) | 664.0 3 722.1 2 769.6 1 | 4.3 8 21 2 100 5 | (M1,E2) (M1+E2) (M1) | 114.1 55.8 8.4 | (11/2+) (9/2+) (7/2+) | |
| 889.1 10 | A | (11/2+) | 706.3 2 775.0 1 833.3 1 880.8 1 | 1.12 13 ≈3.9 29 2 100 5 | (M1) (E2+M1) E2 | 182.5 114.1 55.8 8.4 | (13/2+) (11/2+) (9/2+) (7/2+) | |
| 942 4 | C | (13/2+) | ||||||
| 957.5 10 | A C | (13/2+) | 694.5 3 775.0 1 843.4 1 901.6 1 | 12 3 ≈32 92 8 100 8 | (M1+E2) | 263.0 182.5 114.1 55.8 | (15/2+) (13/2+) (11/2+) (9/2+) | |
| E(level) (keV) | XREF | Jπ(level) | T1/2(level) | E(γ) (keV) | I(γ) | M(γ) | Final Levels | |
| 1239.0 10 | A | (11/2+) | 281.4 1 349.9 1 461.0 1 1056.2 4 1124.9 2 1183.0 2 1230.6 2 | 8.6 6 100 5 11.0 7 0.7 1 3.3 4 8.8 6 16.7 12 | M1(+E2) M1 (M1) | 957.5 889.1 778.0 182.5 114.1 55.8 8.4 | (13/2+) (11/2+) (9/2+) (13/2+) (11/2+) (9/2+) (7/2+) | |
| 1264.9 10 | A | (11/2+) | 307.4 1 375.8 1 487.1 2 1151.0 2 1209.1 2 1256.6 2 | 9.7 8 100 6 3.0 6 4.1 6 9.5 8 17.6 14 | M1+E2 M1 | 957.5 889.1 778.0 114.1 55.8 8.4 | (13/2+) (11/2+) (9/2+) (11/2+) (9/2+) (7/2+) | |
| 1301.4 11 | A | (7/2+,9/2,11/2) | 1245.6 4 1293.0 3 | 16 2 100 8 | 55.8 8.4 | (9/2+) (7/2+) | ||
| 1307.2 10 | A | (7/2+,9/2,11/2+) | 1193.0 2 1251.2 2 1298.8 3 | 21 2 45 4 100 7 | 114.1 55.8 8.4 | (11/2+) (9/2+) (7/2+) | ||
| 1357.0 11 | A | (7/2+,9/2,11/2+) | 1242.8 4 1301.2 3 1348.6 3 | 100 10 190 19 63 6 | 114.1 55.8 8.4 | (11/2+) (9/2+) (7/2+) | ||
E(level): The level energies from 251Fm ε decay have been deduced from least-squares fit to Eγ (with E(5/2- level)=31.7 2 calculated from rotational parameter). Levels not seen in 255Md α decay, or 251Fm ε decay are from the (α,t) reaction.
Jπ(level): The band assignments are those proposed by 1978Ah02 on the basis of the results in 251Fm ε decay and 250Cf(α,t).
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 1 - 3/2-[521]. | |||||||
| 0 | 3/2- | 33 h 1 % ε = 99.5 2 % α = 0.5 2 | |||||
| 31.7 10 | 5/2- | ||||||
| 76.2 11 | 7/2- | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 2 - 7/2+[633]. | |||||||
| 8.4 10 | (7/2+) | ||||||
| 55.8 10 | (9/2+) | 47.48 6 | | M1+E2 | 8.4 | (7/2+) | |
| 114.1 10 | (11/2+) | ||||||
| 182.5 10 | (13/2+) | ||||||
| 263.0 11 | (15/2+) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 3 - 1/2-[521]. | |||||||
| 411 2 | (1/2-) | ||||||
| 452 2 | (5/2-) | ||||||
| 548 2 | (7/2-,9/2-) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 4 - 7/2-[514]. | |||||||
| 461.5 10 | 7/2- | ||||||
| 523.9 10 | (9/2-) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 5 - 1/2+[400] | |||||||
| 661 3 | (1/2+) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 6 - 9/2+[624]. | |||||||
| 778.0 10 | (9/2+) | ||||||
| 942 4 | (13/2+) | ||||||
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) | I(γ) | M(γ) | Final Levels | |
| Band 7 - 7/2+[633]+2+ VIB, Kπ=11/2+. | |||||||
| 889.1 10 | (11/2+) | ||||||
| 957.5 10 | (13/2+) | 694.5 3 775.0 1 843.4 1 901.6 1 | 12 3 ≈32 92 8 100 8 | (M1+E2) | 263.0 182.5 114.1 55.8 | (15/2+) (13/2+) (11/2+) (9/2+) | |
| E(level) (keV) | Jπ(level) | T1/2(level) | E(γ) (keV) | Multipolarity | Mixing Ratio | Conversion Coefficient | Additional Data |
| 55.8 | (9/2+) | 47.48 6 | M1+E2 | 0.18 7 | 107 | α=107 21, α(L)=79 15, α(M)=20 5, α(N)=5.7 13, α(O)=1.5 3, α(P)=0.27 5, α(Q)=0.0123 3, α(N+)=7.4 16 | |
| 461.5 | 7/2- | 385.3 2 | (M1) | 0.938 | α=0.938, α(K)=0.731 11, α(L)=0.1550 22, α(M)=0.0381 6, α(N)=0.01060 15, α(O)=0.00277 4, α(P)=0.000537 8, α(Q)=3.06×10-5 5, α(N+)=0.01394 20 | ||
| 7/2- | 405.6 1 | (E1+M2) | 0.160 13 | 0.078 | α=0.078 9, α(K)=0.057 7, α(L)=0.0159 20, α(M)=0.0041 5, α(N)=0.00114 15, α(O)=0.00030 4, α(P)=5.6×10-5 8, α(Q)=3.0E-6 4, α(N+)=0.00150 19 | ||
| 7/2- | 429.7 1 | M1+E2 | 0.56 30 | 0.55 | α=0.55 11, α(K)=0.42 10, α(L)=0.097 14, α(M)=0.024 4, α(N)=0.0067 9, α(O)=0.00175 24, α(P)=0.00034 5, α(Q)=1.8×10-5 4, α(N+)=0.0088 12 | ||
| 7/2- | 453.1 1 | (E1+M2) | 0.220 15 | 0.090 | α=0.090 10, α(K)=0.065 7, α(L)=0.0183 21, α(M)=0.0047 6, α(N)=0.00132 15, α(O)=0.00034 4, α(P)=6.5×10-5 8, α(Q)=3.5E-6 4, α(N+)=0.00173 20 | ||
| 778.0 | (9/2+) | 664.0 3 | (M1,E2) | 0.12 | α=0.12 9, α(K)=0.09 8, α(L)=0.023 13, α(M)=0.006 3, α(N)=0.0016 9, α(O)=0.00041 22, α(P)=8.E-5 5, α(Q)=4.E-6 3, α(N+)=0.0021 11 | ||
| (9/2+) | 722.1 2 | (M1+E2) | 0.6 3 | 0.13 | α=0.13 3, α(K)=0.103 21, α(L)=0.023 4, α(M)=0.0056 9, α(N)=0.00155 24, α(O)=0.00040 7, α(P)=7.8×10-5 13, α(Q)=4.3E-6 9, α(N+)=0.0020 4 | ||
| (9/2+) | 769.6 1 | (M1) | 0.1429 | α=0.1429, α(K)=0.1117 16, α(L)=0.0234 4, α(M)=0.00573 8, α(N)=0.001592 23, α(O)=0.000417 6, α(P)=8.07×10-5 12, α(Q)=4.60E-6 7, α(N+)=0.00209 3 | |||
| 889.1 | (11/2+) | 706.3 2 | (M1) | 0.180 | α=0.180, α(K)=0.1407 20, α(L)=0.0295 5, α(M)=0.00724 11, α(N)=0.00201 3, α(O)=0.000527 8, α(P)=0.0001019 15, α(Q)=5.81×10-6 9, α(N+)=0.00265 4 | ||
| (11/2+) | 833.3 1 | (E2+M1) | 2.1 +5-3 | 0.040 | α=0.040 6, α(K)=0.030 5, α(L)=0.0080 8, α(M)=0.00202 18, α(N)=0.00056 5, α(O)=0.000146 14, α(P)=2.7×10-5 3, α(Q)=1.26E-6 17, α(N+)=0.00074 7 | ||
| (11/2+) | 880.8 1 | E2 | 0.0209 | α=0.0209, α(K)=0.01447 21, α(L)=0.00476 7, α(M)=0.001231 18, α(N)=0.000344 5, α(O)=8.86×10-5 13, α(P)=1.627E-5 23, α(Q)=6.28E-7 9, α(N+)=0.000449 7 | |||
| 957.5 | (13/2+) | 843.4 1 | (M1+E2) | 0.8 3 | 0.077 | α=0.077 17, α(K)=0.059 14, α(L)=0.0132 25, α(M)=0.0033 6, α(N)=0.00091 17, α(O)=0.00024 5, α(P)=4.5×10-5 9, α(Q)=2.5E-6 6, α(N+)=0.00119 22 | |
| 1239.0 | (11/2+) | 281.4 1 | M1(+E2) | 0.4 2 | 1.98 | α=1.98 24, α(K)=1.51 21, α(L)=0.347 23, α(M)=0.086 5, α(N)=0.0240 14, α(O)=0.0063 4, α(P)=0.00120 9, α(Q)=6.4×10-5 9, α(N+)=0.0316 18 | |
| (11/2+) | 349.9 1 | M1 | 1.223 | α=1.223, α(K)=0.953 14, α(L)=0.202 3, α(M)=0.0498 7, α(N)=0.01384 20, α(O)=0.00363 5, α(P)=0.000702 10, α(Q)=4.00×10-5 6, α(N+)=0.0182 3 | |||
| (11/2+) | 461.0 1 | (M1) | 0.574 | α=0.574, α(K)=0.447 7, α(L)=0.0946 14, α(M)=0.0232 4, α(N)=0.00646 9, α(O)=0.001691 24, α(P)=0.000327 5, α(Q)=1.87×10-5 3, α(N+)=0.00850 12 | |||
| 1264.9 | (11/2+) | 307.4 1 | M1+E2 | 0.5 2 | 1.45 | α=1.45 20, α(K)=1.11 17, α(L)=0.260 20, α(M)=0.065 5, α(N)=0.0181 12, α(O)=0.0047 4, α(P)=0.00090 8, α(Q)=4.7×10-5 7, α(N+)=0.0237 16 | |
| (11/2+) | 375.8 1 | M1 | 1.005 | α=1.005, α(K)=0.783 11, α(L)=0.1661 24, α(M)=0.0408 6, α(N)=0.01136 16, α(O)=0.00297 5, α(P)=0.000575 8, α(Q)=3.28×10-5 5, α(N+)=0.01494 21 |
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0 | 3/2- | 33 h 1 % ε = 99.5 2 % α = 0.5 2 | E(level): 3/2-[521]. |
| 8.4 | (7/2+) | E(level): 7/2+[633]. | |
| 31.7 | 5/2- | E(level): 3/2-[521]. | |
| 55.8 | (9/2+) | E(level): 7/2+[633]. | |
| 76.2 | 7/2- | E(level): 3/2-[521]. | |
| 114.1 | (11/2+) | E(level): 7/2+[633]. | |
| 182.5 | (13/2+) | E(level): 7/2+[633]. | |
| 263.0 | (15/2+) | E(level): 7/2+[633]. | |
| 411 | (1/2-) | E(level): 1/2-[521]. Jπ(level): From comparison of (α,t) spectroscopic factors with Nilsson model calculations, the 411, 452 and 548 levels belong to the 1/2[521] rotational band. | |
| 452 | (5/2-) | E(level): 1/2-[521]. Jπ(level): From comparison of (α,t) spectroscopic factors with Nilsson model calculations, the 411, 452 and 548 levels belong to the 1/2[521] rotational band. | |
| 461.5 | 7/2- | E(level): 7/2-[514]. | |
| 523.9 | (9/2-) | E(level): 7/2-[514]. | |
| 548 | (7/2-,9/2-) | E(level): 1/2-[521]. Jπ(level): From comparison of (α,t) spectroscopic factors with Nilsson model calculations, the 411, 452 and 548 levels belong to the 1/2[521] rotational band. | |
| 661 | (1/2+) | E(level): 1/2+[400]. | |
| 778.0 | (9/2+) | E(level): 9/2+[624]. | |
| 889.1 | (11/2+) | E(level): 7/2+[633]+2+ VIB, Kπ=11/2+. | |
| 942 | (13/2+) | E(level): 9/2+[624]. | |
| 957.5 | (13/2+) | E(level): 7/2+[633]+2+ VIB, Kπ=11/2+. |
Calculations, compilations:
Favored α decay: 1993Bu09, 1992Bu03
Ground-state properties: 1997Mo25, 1995Mo29
Heavy cluster spontaneous emission: 1985Po15
Deformation, Pairing gap, Single-particle energies: 2004Pa40
Single-particle Nilsson levels: 1994Cw02, 2010Ad19
Alpha decay, t, branching ratios: 2010Ni02
Q(α), T1/2: 2011Sa20, 2008Do12
1994Cw02 calculated the following single-particle level sequence: g.s. 7/2[633], 0.30 MeV 3/2[521], 0.35 MeV 1/2[521], 0.73 MeV 7/2[514], 0.79 MeV 5/2[642], 0.80 MeV 1/2[660]
2004Pa40 calculated the following single-particle level sequence: g.s. 7/2[633], 0.20 MeV 3/2[521], 0.20 MeV 1/2[521], 0.55 MeV 1/2[400], 0.58 MeV 5/2[642], 0.60 MeV 7/2[514]
Gammas: All γ-ray data are from 251Fm ε decay (1978Ah02)
Q-value: Estimated ΔS(n)=100 (2012Wa38)