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.

List of isotopes

|-id=Tennessine-293 | ²⁹³Ts | style="text-align:right" | 117 | style="text-align:right" | 176 | 293.20873(84)# | <br />[] | α | ²⁸⁹Mc | |-id=Tennessine-294 | ²⁹⁴Ts | style="text-align:right" | 117 | style="text-align:right" | 177 | 294.21084(64)# | <br />[] | α | ²⁹⁰Mc |

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.

Hot fusion

²⁴⁹Bk(⁴⁸Ca,xn)^{297−x}Ts (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.

<br /> 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&nbsp;MeV (dose 2×10¹⁹) and 39&nbsp;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

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

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, ^{289–303}Ts) to be around 0.1–40&nbsp;ms.

References