Английская Википедия:Isotopes of tennessine

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Шаблон:Short description Шаблон:Infobox tennessine isotopes 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.

List of isotopes

Шаблон:Isotopes table |- | ²⁹³Ts | style="text-align:right" | 117 | style="text-align:right" | 176 | 293.20873(84)# | Шаблон:Val | α | ²⁸⁹Mc | |- | ²⁹⁴Ts | style="text-align:right" | 117 | style="text-align:right" | 177 | 294.21084(64)# | Шаблон:Val | α | ²⁹⁰Mc | Шаблон:Isotopes table/footer

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	Шаблон:Unk
209Bi	82Se	291Ts	Шаблон:Unk
238U	55Mn	293Ts	Шаблон:Unk
243Am	50Ti	293Ts	Шаблон:Unk
249Bk	48Ca	297Ts	Шаблон:Yes

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. 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[4]

  Calculated decay chains from the parent nuclei ²⁹³Ts and ²⁹⁴Ts

The team published a paper in April 2010 (first results were presented in January 2010) 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.

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
209Bi	79Se	288Ts	1n (287Ts)	0.2 pb	DNS
232Th	59Co	291Ts	2n (289Ts)	0.1 pb	DNS
238U	55Mn	293Ts	2-3n (291,290Ts)	70 fb	DNS
244Pu	51V	295Ts	3n (292Ts)	0.6 pb	DNS
248Cm	45Sc	293Ts	4n (289Ts)	2.9 pb	DNS
246Cm	45Sc	291Ts	4n (287Ts)	1 pb	DNS
249Bk	48Ca	297Ts	3n (294Ts)	2.1 pb ; 3 pb	DNS
247Bk	48Ca	295Ts	3n (292Ts)	0.8, 0.9 pb	DNS

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.