Isotopes of tennessine
Tennessine (117Ts) is the most-recently synthesized synthetic element, and much of the data is hypothetical. As for any synthetic element, a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first (and so far only) isotopes to be synthesized were 293Ts and 294Ts in 2009. The longer-lived isotope is 294Ts with a half-life of 51 ms.
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List of isotopes
Nuclide |
Z | N | Isotopic mass (Da) [n 1][n 2] |
Half-life |
Decay mode |
Daughter isotope |
Spin and parity |
---|---|---|---|---|---|---|---|
293Ts | 117 | 176 | 293.20824(89)# | 22 (+8−4) ms[3] | α | 289Mc | |
294Ts | 117 | 177 | 294.21046(74)# | 51 (+41−16) ms[4] | α | 290Mc |
- ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
Isotopes and nuclear properties
Nucleosynthesis
Target-projectile combinations leading to Z=117 compound nuclei
The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with atomic number 117.
Target | Projectile | CN | Attempt result |
---|---|---|---|
208Pb | 81Br | 289Ts | Reaction yet to be attempted |
209Bi | 82Se | 291Ts | Reaction yet to be attempted |
238U | 55Mn | 293Ts | Reaction yet to be attempted |
243Am | 50Ti | 293Ts | Planned reaction |
249Bk | 48Ca | 297Ts | Successful reaction |
Hot fusion
249Bk (48Ca, xn)297−xTs (x=3,4)
Between July 2009 and February 2010, the team at the JINR (Flerov Laboratory of Nuclear Reactions) ran a 7-month-long experiment to synthesize tennessine using the reaction above.[5] The expected cross-section was of the order of 2 pb. The expected evaporation residues, 293Ts and 294Ts, were predicted to decay via relatively long decay chains as far as isotopes of dubnium or lawrencium.
- Calculated decay chains from the parent nuclei 293Ts and 294Ts[6]
The team published a scientific paper in April 2010 (first results were presented in January 2010[7]) that six atoms of the neighbouring isotopes 294Ts (one atom) and 293Ts (five atoms) were detected. The heavier isotope decayed by the successive emission of six alpha particles down as far as the new isotope 270Db, which underwent apparent spontaneous fission. On the other hand, the lighter odd-even isotope decayed by the emission of just three alpha particles, as far as 281Rg, which underwent spontaneous fission. The reaction was run at two different excitation energies of 35 MeV (dose 2×1019) and 39 MeV (dose 2.4×1019). Initial decay data was published as a preliminary presentation on the JINR website.[8]
A further experiment in May 2010, aimed at studying the chemistry of the granddaughter of tennessine, nihonium, identified a further two atoms of 286Nh from the decay of 294Ts. The original experiment was repeated successfully by the same collaboration in 2012 and by a joint German–American team in May 2014, confirming the discovery.
Chronology of isotope discovery
Isotope | Year discovered | Discovery reaction |
---|---|---|
294Ts | 2009 | 249Bk(48Ca,3n) |
293Ts | 2009 | 249Bk(48Ca,4n) |
Theoretical calculations
Evaporation residue cross sections
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) | σmax | Model | Ref |
---|---|---|---|---|---|---|
209Bi | 82Se | 291Ts | 1n (290Ts) | 15 fb | DNS | [9] |
209Bi | 79Se | 288Ts | 1n (287Ts) | 0.2 pb | DNS | [9] |
232Th | 59Co | 291Ts | 2n (289Ts) | 0.1 pb | DNS | [9] |
238U | 55Mn | 293Ts | 2-3n (291,290Ts) | 70 fb | DNS | [9] |
244Pu | 51V | 295Ts | 3n (292Ts) | 0.6 pb | DNS | [9] |
248Cm | 45Sc | 293Ts | 4n (289Ts) | 2.9 pb | DNS | [9] |
246Cm | 45Sc | 291Ts | 4n (287Ts) | 1 pb | DNS | [9] |
249Bk | 48Ca | 297Ts | 3n (294Ts) | 2.1 pb ; 3 pb | DNS | [9][10] |
247Bk | 48Ca | 295Ts | 3n (292Ts) | 0.8, 0.9 pb | DNS | [9][10] |
Decay characteristics
Theoretical calculations in a quantum tunneling model with mass estimates from a macroscopic-microscopic model predict the alpha-decay half-lives of isotopes of tennessine (namely, 289–303Ts) to be around 0.1–40 ms.[11][12][13]
References
- Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501. PMID 24836239.
- Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C. 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.
- Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C. 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.
- Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501. hdl:1885/148814. PMID 24836239.
- Tennessine – the 117th element at AtomInfo.ru
- Roman Sagaidak. "Experiment setting on synthesis of superheavy nuclei in fusion-evaporation reactions. Preparation to synthesis of new element with Z=117" (PDF). Archived from the original (PDF) on 2011-07-03. Retrieved 2009-07-07.
- Recommendations: 31st meeting, PAC for Nuclear Physics Archived 2010-04-14 at the Wayback Machine
- Walter Grenier: Recommendations, a PowerPoint presentation at the January 2010 meeting of the PAC for Nuclear Physics
- Zhao-Qing, Feng; Gen-Ming, Jin; Ming-Hui, Huang; Zai-Guo, Gan; Nan, Wang; Jun-Qing, Li (2007). "Possible Way to Synthesize Superheavy Element Z = 117". Chinese Physics Letters. 24 (9): 2551. arXiv:0708.0159. Bibcode:2007ChPhL..24.2551F. doi:10.1088/0256-307X/24/9/024.
- 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. arXiv:0803.1117. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003.
- C. Samanta; P. Roy Chowdhury; D. N. Basu (2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nuclear Physics A. 789 (1–4): 142–154. arXiv:nucl-th/0703086. Bibcode:2007NuPhA.789..142S. doi:10.1016/j.nuclphysa.2007.04.001.
- P. Roy Chowdhury; C. Samanta; D. N. Basu (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Physical Review C. 77 (4): 044603. arXiv:0802.3837. Bibcode:2008PhRvC..77d4603C. doi:10.1103/PhysRevC.77.044603.
- P. Roy Chowdhury; C. Samanta; D. N. Basu (2008). "Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130". Atomic Data and Nuclear Data Tables. 94 (6): 781–806. arXiv:0802.4161. Bibcode:2008ADNDT..94..781C. doi:10.1016/j.adt.2008.01.003.
External sources
- Isotope masses from:
- M. Wang; G. Audi; A. H. Wapstra; F. G. Kondev; M. MacCormick; X. Xu; et al. (2012). "The AME2012 atomic mass evaluation (II). Tables, graphs and references" (PDF). Chinese Physics C. 36 (12): 1603–2014. Bibcode:2012ChPhC..36....3M. doi:10.1088/1674-1137/36/12/003.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.