Tennessine-294
Isotopes of tennessine
Nuclides with atomic number of 117 but with different mass numbers
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.
| Nuclide |
Z | N | Isotopic mass (Da)[4] [n 1][n 2] |
Half-life |
Decay mode |
Daughter isotope |
Spin and parity | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 293Ts | 117 | 176 | 293.20873(84)# | 22+8 −4 ms[3] |
α | 289Mc | |||||||||||||
| 294Ts | 117 | 177 | 294.21084(64)# | 51+41 −16 ms[2] |
α | 290Mc | |||||||||||||
| This table header & footer: | |||||||||||||||||||
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 | Yet to be attempted |
| 209Bi | 82Se | 291Ts | Yet to be attempted |
| 238U | 55Mn | 293Ts | Yet to be attempted |
| 243Am | 50Ti | 293Ts | Yet to be attempted |
| 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 paper in April 2010 (first results were presented in January 2010[7]) that six atoms of the isotopes 294Ts (one atom) and 293Ts (five atoms) were detected. 294Ts decayed by six alpha decays down as far as the new isotope 270Db, which underwent apparent spontaneous fission. The lighter odd-even isotope underwent just three alpha decays, as far as 281Rg, which underwent spontaneous fission. The reaction was run at two different excitation energies, 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 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 | 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]
- Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
- 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.
- Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
- 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. S2CID 250860387.
- 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. S2CID 18647291.
- 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. S2CID 7496348.
- 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. S2CID 119207807.
- 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. S2CID 96718440.