Isotopes of ununoctium

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Ununoctium (Uuo) is a synthetic element created in particle colliders, and thus a standard atomic mass cannot be given. Like all synthetic elements, it has no stable isotopes. The first (and so far only) isotope to be synthesized was 294Uuo in 2006; it has a half-life of 890 microseconds.

Table[edit]

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life decay mode(s) daughter
isotope(s)
nuclear
spin
294Uuo 118 176 294.21392(71)# 890 µs α 290Lv

Notes[edit]

  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values from Ame2003 denote one standard deviation. Values from IUPAC are expanded uncertainties.

Theoretical[edit]

Theoretical calculations done on the synthetic pathways for, and the half-life of, other isotopes have shown that some could be slightly more stable than the synthesized isotope 294Uuo, most likely 293Uuo, 295Uuo, 296Uuo, 297Uuo, 298Uuo, 300Uuo and 302Uuo.[1][2][3] Of these, 297Uuo, might provide the best chances for obtaining longer-lived nuclei,[1][3] and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around 313Uuo, could also provide longer-lived nuclei.[4]

Target-projectile combinations leading to Z=118 compound nuclei[edit]

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z=118.

Target Projectile CN Attempt result
160Gd 136Xe 296Uuo* Reaction yet to be attempted
208Pb 86Kr 294Uuo* Failure to date
232Th 64Ni 296Uuo* Reaction yet to be attempted
238U 58Fe 296Uuo* Reaction yet to be attempted
244Pu 54Cr 298Uuo* Reaction yet to be attempted
248Cm 50Ti 298Uuo* Reaction yet to be attempted
250Cm 50Ti 300Uuo* Reaction yet to be attempted
249Cf 48Ca 297Uuo* Successful reaction
252Cf 48Ca 300Uuo* Reaction yet to be attempted
257Fm 40Ar 297Uuo* Reaction yet to be attempted

Theoretical calculations on evaporation cross sections[edit]

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system ; σ = cross section

Target Projectile CN Channel (product) σ max Model Ref
208Pb 86Kr 294Uuo 1n (293Uuo) 0.1 pb DNS [5]
208Pb 85Kr 293Uuo 1n (292Uuo) 0.18 pb DNS [5]
252Cf 48Ca 300Uuo 3n (297Uuo) 1.2 pb DNS [6]
251Cf 48Ca 299Uuo 3n (296Uuo) 1.2 pb DNS [6]
249Cf 48Ca 297Uuo 3n (294Uuo) 0.3 pb DNS [6]

References[edit]

  1. ^ a b P. Roy Chowdhury; C. Samanta; D. N. Basu (January 26, 2006). "α decay half-lives of new superheavy elements". Physical Review C. 73: 014612. arXiv:nucl-th/0507054free to read. Bibcode:2006PhRvC..73a4612C. doi:10.1103/PhysRevC.73.014612. Retrieved 2008-01-18. 
  2. ^ C. Samanta; P. Roy Chowdhury; D. N. Basu (April 6, 2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nuclear Physics A. 789 (1–4): 142–154. arXiv:nucl-th/0703086free to read. Bibcode:2007NuPhA.789..142S. doi:10.1016/j.nuclphysa.2007.04.001. Retrieved 2008-01-18. 
  3. ^ a b G. Royer; K. Zbiri; C. Bonilla (2004). "Entrance channels and alpha decay half-lives of the heaviest elements". Nuclear Physics A. 730 (3–4): 355–376. arXiv:nucl-th/0410048free to read. Bibcode:2004NuPhA.730..355R. doi:10.1016/j.nuclphysa.2003.11.010. Retrieved 2008-01-18. 
  4. ^ S. B. Duarte; O. A. P. Tavares; M. Gonçalves; O. Rodríguez; F. Guzmán; T. N. Barbosa; F. García; A. Dimarco (2004). "Half-life predictions for decay modes of superheavy nuclei". Journal of Physics G: Nuclear and Particle Physics. 30 (10): 1487–1494. Bibcode:2004JPhG...30.1487D. doi:10.1088/0954-3899/30/10/014. Retrieved 2008-01-18. 
  5. ^ a b Feng, Zhao-Qing; Jin, Gen-Ming; Li, Jun-Qing; Scheid, Werner (2007). "Formation of superheavy nuclei in cold fusion reactions". Physical Review C. 76 (4): 044606. arXiv:0707.2588free to read. Bibcode:2007PhRvC..76d4606F. doi:10.1103/PhysRevC.76.044606. 
  6. ^ a b c Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816 (1–4): 33–51. arXiv:0803.1117free to read. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003. 
Isotopes of ununseptium Isotopes of ununoctium Isotopes of ununennium
Table of nuclides