277 COMMENTS 00NDS 200006 277 C TITL$Evaluation for A=277 277 c AUTH$R.B. Firestone, and J. Gilat 277 c INST$Nuclear Science Division 277 #c Lawrence Berkeley National Laboratory 277 #c 1 Cyclotron Road 277 #c Berkeley, California 94720 277 c ABST$These data are mainly from cold fusion experiments performed at 277 2c GSI/Ship, Dubna, and Berkeley. The experiments generally involve mass 277 3c separation of heavy elements followed by implantation into a 277 4c position-sensitive alpha-particle detector. The position, energy, and 277 5c time with respect to implantation are recorded. Successive decays at a 277 6c given position are correlated into a decay chain linking the heaviest 277 7c cold fusion product to lighter nuclei which also may be previously 277 8c unknown. In some cases the decay chain ends in spontaneous fission, 277 9c and some alpha particles escape the detector leaving only partial 277 ac energy signals. When multiple alpha decay chains are observed for a 277 bc given parent, the evaluators have made subjective assignments to 277 cc isomer and ground states based on comparable alpha particle energies 277 dc and decay times. 277 c CUT$April 1, 2000 277 C CIT$NDS 90, 391 (2000) 277 c COMM$Significant use is made of alpha energy and half-life calcuations 277 2c in making isotope assignments. The decay chains starting at A=289 and 277 3c A=293 are not connected to known nuclei and are assigned, in part, on 277 4c the basis of reaction systematics. The evaluators have made extensive 277 5c use of calculated masses and lifetimes from 1997Mo25. These authors 277 6c calculate alpha-decay lifetimes using the Viola-Seaborg relation 277 8c log(T{-1/2}(|a))=(aZ + b)|*Q(|a){+1/2} +(cZ + d) where T{-1/2}(|a) is 277 ac in seconds, Q(|a) in MeV, and a=1.66175, b=-8.5166, c=-0.20228, and 277 bc d=-33.9069. 277 c Various spin and parity assignments have been proposed for the these 277 2c superheavy elements. Some of the suggested values are provided by the 277 3c evaluators without comment. The reader is referred to the original 277 4c publications for details. From Nilsson model calculations (1996FiZY), 277 5c at zero deformation there is a shell gap at Z=114 but no strong 277 6c neutron shell gap for N>126. The available single-particle shell model 277 7c states at Z<114 are 2f7/2, 1i13/2, and 1h9/2, and for Z>114 2f5/2 and 277 8c 3p3/2. The expected order of shell model neutron states for N>126 is 277 9c 2g9/2, 1i11/2, 1j15/2, 3d5/2, 2g7/2, 4s1/2, 3d3/2, and 2h11/2. In the 277 ac case of a finite deformation, the theoretical level structure picture 277 bc becomes much more complex. The data are too limited to distinguish the 277 cc various configurations. However, there are numerous instances of 277 dc isomerism consistent with the wide range of available spin states. 277 ec There is also strong evidence of alpha decay to excited states 277 fc indicating that ground state structure may change substantially from 277 gc parent to daughter. The evaluators emphasize that there is too little 277 hc data available to infer Q(|b{+-})values and assign isotope and isomer 277 ic levels with great confidence. 277 c These evaluations are dedicated to the memory of Glenn Seaborg. 277 REFERENCES 200006 277 R 1995HO27 JOUR RAACA 70/71 135 277 R 1996FIZY BOOK Table of Isotopes, 8th Ed., John Wiley and Sons 277 R 1996HO13 JOUR ZPAAD 354 229 277 R 1997MO25 JOUR ADNDA 66 131 277 R 1997SM03 JOUR PRVCA 56 812 277 R 1999GHZZ PC A Ghiorso 277 R 1999NI03 JOUR PRLTA 83 1104 277 R 2002NI10 JOUR PRLTA 89 039901 277 R 2003GR26 JOUR ZAANE 18 633 277HS ADOPTED LEVELS 00NDS 200006 277HS H TYP=MOD$AUT=B. SINGH$DAT=23-FEB-2004$COM=SYMBOL 277HS2 H DS SUBSTITUTED FOR Z=110 277HS H TYP=FUL$AUT=R.B. Firestone, and J. Gilat$CIT=NDS 90, 391 (2000)$ 277HS2 H CUT=1-APR-2000$ 277HS c 1999GhZZ: produced by {+244}Pu({+48}Ca,3n). Dubna gas-filled separator. 277HS2c One chain of |a events was observed in 4-|p silicon-strip detector. 277HS t E1=9710 keV, t1=30 s - assigned to 28914 277HS2t E2=8670 keV, t2=15 min - assigned to 28512 277HS3t E3=8830 keV, t3=1.6 min - E3=4200+4630 (sum event) assigned to {+281}Ds 277HS4t E4=120+50 MeV, t4=17 min - SF event assigned to {+277}Hs. 277HS c Assignments are based on E versus T{-1/2} relationships for the three 277HS2c |a's. Possible assignment to {+290}113 or {+287}112 decay chain cannot 277HS3c be ruled out. The probability that the decay chain is accidental has 277HS4c been estimated at 1|*10{+-5} by the authors. This assignment is 277HS5c considered tentative by the evaluator until a connection to known 277HS6c nuclides is established. 277HS Q 490 CA 5130 CA 4850 CA 8740 CA 1997MO25 277HS L 0+X 12 M +54-6 ? 277HS2 L %SF=?$%A=? 277HS cL %A,%SF$predicted |b (1997Mo25) half-life much 277HS2cL longer than that predicted for |a emission; 277HS3cL or observed for spontaneous fission. 277HS cL T$maximum likelihood value for single event. 277HS2cL T{-1/2}(|a)=23 min from Q(|a) of 1997Mo25 and Viola-Seaborg relation. 277HS cL J$1997Mo25 calculate J|p=3/2+ 277HS 281DS A DECAY 1999GHZZ 00NDS 200006 277HS H TYP=MOD$AUT=B. SINGH$DAT=23-FEB-2004$COM=SYMBOL 277HS2 H DS SUBSTITUTED FOR Z=110 277HS H TYP=FUL$AUT=R.B. Firestone, and J. Gilat$CIT=NDS 90, 391 (2000)$ 277HS2 H CUT=1-APR-2000$ 277HS c Single |a chain event observed. See {+289}114 adopted levels. 281DS P 0+X 1.1 M +50-6 8550 CA 277HS N 1 277HS L 0+X 12 M +54-6 ? 277HS A 8830 70 100 AP 277HS cA E$uncertainty assumed by the evaluator. 277HS cA IA$one event observed 277DS ADOPTED LEVELS 00NDS 200006 277DS H TYP=MOD$AUT=B. SINGH$DAT=23-FEB-2004$COM=ALL DATA 277DS2 H FROM 1999NI03 OMITTED AS PER 2003GR26 AND 2002NI10 277DS H TYP=FUL$AUT=R.B. Firestone, and J. Gilat$CIT=NDS 90, 391 (2000)$ 277DS2 H CUT=1-APR-2000$ 277DS Q -3180 CA 5240 CA 3360 CA 10800 CA 1997MO25,1997SM03 277DS c Data reported in 1999Ni03 have been retracted (2002Ni10) and have 277DS2c not been confirmed in a repeated experiment at LBNL (2003Gr26). 277DS3c Thus {+277}Ds remains unobserved. 277DS 28112 A DECAY 00NDS 200006 277DS H TYP=MOD$AUT=B. SINGH$DAT=23-FEB-2004$COM=ALL DATA 277DS2 H FROM 1999NI03 OMITTED AS PER 2003GR26 AND 2002NI10 277DS H TYP=FUL$AUT=R.B. Firestone, and J. Gilat$CIT=NDS 90, 391 (2000)$ 277DS2 H CUT=1-APR-2000$ 277DS c Data reported in 1999Ni03 have been retracted (2002Ni10) and have 277DS2c not been confirmed in a repeated experiment at LBNL (2003Gr26). 277DS3c Thus {+281}112 remains unobserved. 27712 ADOPTED LEVELS 00NDS 200006 27712 H TYP=FUL$AUT=R.B. Firestone, and J. Gilat$CIT=NDS 90, 391 (2000)$ 277122 H CUT=1-APR-2000$ 27712 c 1996Ho13: GSI/ship cold fusion experiment. {+208}Pb({+70}Zn,n) at 277122c 4.91 MEV/nucleon. Total of 3.4|*10{+18} projectile particles. 277123c Observed position and time correlated chains of |a particle events. 277124c Determined |a energies and time intervals between 277125c successive particles. Assigned to decay of {+277}112 by consistency of 277126c lower chain member energies and lifetimes with known Rf and Sg data. 277127c The measured |a energies and emission times for the second member of 277128c two event chains (decay of {+273}112 ) were: 277129c E1=11450 {I20} keV, t1=280 |ms; E2=11650 {I20} keV, t2=400 |ms, 27712Ac indicating one parent and two daughter states. 27712Bc First chain member transitions correspond to decay of {+277}112 and 27712Cc identify levels in 27310. 27712 Q -5290 CA 6080 CA 2050 CA 11820 20 1997MO25 27712 cQ QA$assuming 11650 {I20} transition populates the g.s. 1997Mo25 277122cQ calculate 12080 keV. 27712 L 0+X 0.24 MS +43-9 277122 L %A=100 27712 cL J$from their calcuations 1997Mo25 suggest J|p=3/2+ 27712 cL T$from 1996Ho13. Maximum likelyhood value assuming |a events at 277122cL 280 |ms and 400 |ms deexcite the same parent level. 27712 cL %A$predicted |b (1997Mo25) and SF (1995Ho27, 1997Sm03) half-lives 277122cL much longer than those predicted and observed for |a emission. 277123cL No spontaneous fission events observed in 1996Ho13.