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Oct 16

Discovery of Element 118 by Oganessian, Don’t Call it Ununoctium

by mitch | Categories: nuclear chemistry | (9879 Views)

Element 118 has had a sordid past. It literally is a wonderful case study in scientific fraud and how the culture of science always eventually corrects and catches the dishonest individual. Disregarding the juicy aspects of that salacious back-story and moving forward to the recent discovery claim, by Oganessian for element 118. Surprisingly the article wasn’t published in Nature or Physical Review Letters, but in Phys Rev C (PRC). PRC is a journal for nuclear scientists and it just seems odd to me that they didn’t pick a journal with a higher impact factor. Then again Oganessian is already the man in heavyelement’s research so I guess he doesn’t need to be in the lime-light, although he does seem to have a disproportionate number of first author papers. The 118 decay chain is shown below:

Usually, nuclear scientists in the field will make a new element and check to see if it was really made by seeing if the daughters have the same decay characteristics as those already published, we call this a genetic correlation. In this paper we would check to see if the decay characteristics of element 116, 114, and 112 matches with what we have seen previously. The problem is, no one else but the Russians have ever made those isotopes of 116, 114, and 112. So as of yet, they are unconfirmed and still need to be further investigated themselves! That’s the problem of taking a blind leap of faith and running a 118 experiment, the daughters haven’t been investigated, so you end up trying to prove you made what you made by using various theoretical models that point to similar decay characteristics as you expected. To Organessian’s great credit they did not publish their results on 118, which they technically discovered in 2002, but waited until they did further investigations of 116 and 114 and even several chemistry runs for 112. So, in this paper it all matches up, the decay of 118 matches what they saw for 116 and so on.

Unfortunately, the paper has no smoking gun for 118. I define a smoking gun as being an EVR-a-a-a-sf, the bold indicating that the decay occurred when the beam was turned off. Even without that, the background is low enough, that the probability of random correlations seems low and the data still good. One worrisome thing about the 118 claim are the two 118 alphas with 11.65MeV in energy. See their table below highlighted in red.

212Pom has the exact same alpha energy of 11.65MeV. One would also expect to see 212Pom as a common transfer product contaminant in these reactions. Also, from what I understood from their data analysis code, the first alpha in strip 3 should of turned off the beam, and I didn’t see where they explained why it didn’t. Also, having a mean life-time, for 116, ranging from 98ns to 42ms seems too large, even for just 3 events.

In summary, the problem with the work is that 118 doesn’t decay into the known and investigated regions of the periodic table, like element 110(Ds) and 108(Hs). So we can’t say with 100% certainty they made what they said they did. Until the rest of the nuclear community “catches-up” to the Russians with thorough systematic studies all the way from Roentgenium to element 118, we will not be able to evaluate the claim thoughtfully. And since the Americans and the Germans haven’t been able to prove Russia’s 112 element claim thus far, I doubt anyone will be running a 118 confirmation experiment in the near future.

Note 1: You can download the paper here: Oganessian’s element 118 claim
Note 2: No one in the field will ever call element 118 “ununoctium”, so please don’t embarrass yourself.
Note 3: Edited some of my nonsense because of Grejak’s comment below.
Note 4: I think the Swiss did do a 112 chemistry experiment from the short-lived 114 alpha decay, but that is still unpublished to my knowledge.

Mitch

9 comments

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  1. Billy Jean

    “Ununoctium: The Essentials” (Internet, 2008”) points out that Ununoctium was first produced in 2002 and 2005 at the Russia’s Joint Institute for Nuclear Research (JINR) in Dubna. Its production was announced in 2006, after Scientists from both the JINR and the Lawrence Livermore National Laboratory of California (who worked together at the JINR) discovered that they had produced element 118.

    1. mitch

      Did you read my analysis?

  2. Jim Stavivovik

    Yes, I agree with Billy Jean, that’s irrefutible evidence.

    1. mitch

      Always a good idea to agree with yourself. ;)

  3. Kalin Ravus

    Yes, Billy Jean does put forth undeniable claims. How can you deny what he has stated? Case closed, Billy Jean, you’ve proven it for us all.

  4. mitch

    You do realize your name is colored, uniquely, based on your ip address, right?

  5. Joshg

    alright well, whilst your online I mosewell be serious, I’m researching Ununoctium for a HSC assessment, and I’m trying to understand exactly when it was first produced, according to JINR anyway.

  6. Joshg

    FINE! DONT REPLY THEN!

  7. Bryan Sanctuary

    You say: “Disregarding the juicy aspects of that salacious back-story” Hey I want the salacious details!!! Let us know svp.
    But here we are on Earth which is so cold that most metals are frozen solid, yet in this rare and special environment, bonds can form, water is liquid and chemistry is possible. Raise the temperature a bit, like that of the sun, and chemistry is kaput and the only elements are the lowest in the periodic table. So for me, making elements with large atomic numbers does not hold much interest. What do we learn, beyond our present knowledge of first year chemistry? Besides, they are short lived, unstable, radioactive and cannot form bonds. What good, (I mean what will we learn) if we continue after 118? How about element 230 or higher. The nuclear forces will not hold the nucleons together.

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