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.

Main isotopes of tennessine (₁₁₇Ts)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct ^293Ts[1] syn 20 ms α ^289Mc ^294Ts[2] syn 51 ms α ^290Mc

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

1. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
2. # – 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

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

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)

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

1. 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.
2. 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.
3. 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.
4. 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.
5. Tennessine – the 117th element at AtomInfo.ru
6. 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.
7. Recommendations: 31st meeting, PAC for Nuclear Physics Archived 2010-04-14 at the Wayback Machine
8. Walter Grenier: Recommendations, a PowerPoint presentation at the January 2010 meeting of the PAC for Nuclear Physics
9. 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.
10. 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.
11. 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.
12. 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.
13. 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.