nuclear chemistry

Element 114 is Confirmed

I finally got the green light to talk about element 114 publicly now that our confirmation paper is finally out.[PRL] Element 114 was first claimed to be synthesized by the Russians earlier this decade, but in order for IUPAC to recognize a new element it must be independently confirmed. Making new elements is no easy feat, it takes a lot of dedicated time at cyclotrons to perform these experiments. Because cyclotron time is so precious, it is difficult to get approval to do an experiment that simply proves an other research group’s results. Two of the main reasons we ran this experiment and got approval was to test our new plutonium target box setup and :ahem: disprove the Russians made these elements, but that is not what we observed.

The Russians have a history of publishing their results internally and not submitting their results to peer review. This creates internal reports that have results that sometimes contradict each other. However, in 2007 Orgenessian et. al published a summary of their results in the peer-reviewed Journal of Physics G.[JPhysG] They claim to have seen the following.


In summary they saw two isotopes of element 114, 286114 that decayed to element 112 and 287114 that also decayed to element 112 and then sometimes spontaneously fissioned or mostly decayed to element 110 (darmstadtium). Our own data showed that…


If you make an isotope like 287114 and observe it decay to the known elements 112 and then to darmstadtium, there is little doubt it exists.

Congratulations all around. Hopefully they propose a better name for element 114 that is less divisive than Kurchatovium, the name they proposed for element 104 after the Soviet atomic bomb project leader.

Link to Confirmation Paper: Independent Verification of Element 114 Production in the 48Ca+242Pu Reaction

Press Release: Superheavy Element 114 Confirmed: A Stepping Stone to the Island of Stability

Mitch

tl;dr Element 114 was made independently of the Russians and now they can name it.

By September 24, 2009 12 comments nuclear chemistry

ACS Front Page

facepalm_picard

Looks like ACS is giving the Cold Fusion press conference some nice front page real estate. It is currently prominantly displayed on http://www.acs.org/

I’m getting embarrassed for ACS at this point.

Our recent coverage of the Cold Fusion Press conference: Cold Fusion Has Its Press Conference, Monday Update from ACS in SLC

Pic of the ACS front page is below.

acs-wtf

Mitch

By March 26, 2009 1 comment nuclear chemistry

Cold Fusion Has Its Press Conference

Jeremy and I scored press passes to the recent Cold Fusion Press Conference at the ACS 2009 Spring Meeting. Unfortunately for them I’m a nuclear chemistry PhD student. Jeremy did a quick wrap-up of the press conference,[CB] but I thought it would be useful to have a critical chemist perspective of their recent announcement. The press conference did nothing to address the violation of the most elementary of chemistry and physics that I painstakingly explained in this old post titled “The difference between cold fusion and cold fusion“, but I’ll move on to address their statements.

As this was a press conference and not a scientific talk there wasn’t any data that I can point to as evidence for a cold fusion claim. However, we can tear some sanity from their own words. I asked why they haven’t observed any gamma rays from their cold fusion experiments. Pamela Mosier-Boss was quick to reply that they indeed did measure gamma rays, but they “came in bursts… and are averaged away [over the duration of the experiment]”. Dissect that statement and reflect on it as a scientist. Think to yourself: “Hmmm… clusters of peaks coming all of a sudden but randomly”, “Hmmm… as they run the experiment they see these peaks average out?”, “What does this mean?”. You don’t have to be a spectroscopy expert to figure this one out. The answer is simple, they measured background. Background is a random process, it will come in bursts, they may even cluster to make a peak for a short time, but when you run it over the course of the whole experiment it is “averaged out”; that my friend is background you measured.

At an other point of the conference Mahadeva Srinivasan claims to be able to measure tritium, neutrons, and other ionizing radiation not by actually measuring them, but indirectly from looking at his electrodes and observing craters and holes and trying to ascribe the radiation that caused it. Sounds sort of reasonable unless you’ve ever done any electrodeposition, which is what the process he described would yield if running current through a wire. Here is a picture of an electrodeposited layer of europium oxide my fellow colleagues made in the lab.

europium-electrodeposition1

You can see craters and valleys in the image. I hope their electrodes didn’t look anything as awful as this, but you can see for yourself that electrodeposition can create ugly surfaces. Which was a major reason for the Thin Film community’s move away from electrodeposition and embrace of Sol-Gel techniques, because it causes less cratering and produces homogeneous and uniform films.

So should I believe the claims of a scientist who does not understand the difference between background and peaks? Should I believe a scientist who doesn’t understand the basic consequences of his own technique? You don’t even have to be a nuclear chemist to call bull-shit on this one.

I want to end this on a positive note, because I’ve spent a lot of time hammering these cold fusion people over the years. Honestly, if they are measuring more energy out of their systems than the energy they are putting in, then this is fantastic news. If they see excess heat, then they need to chase this line of inquiry down. But nuclear fusion is not the right path. I truly want to believe these people are capable of measuring the amount of energy in their system versus the energy out correctly. But the electrochemistry they are performing is non-reversible and that makes energy accounting, in their dynamic system, a very difficult mess. The simple act of having gas bubbles float from your electrodes will deposit more energy into your solution, due to friction, then you would expect. And frankly, after listening to these people talk for 45 minutes I don’t believe they are capable of correctly accounting for energy in a dynamic system.

Mitch

P.S. Make up your own mind, a link to the press conference is here, Cold Fusion Press Conference. I ask my question around the 28 minute mark. Aaron Rowe from wired science blog is now my favorite science journalist, his question is asked at 34:50 minute mark.

By March 26, 2009 32 comments nuclear chemistry, opinion

32-electron chemistry

We all remember learning about octets and valence electrons in school. We may also remember the first time we saw an 18-electron transition metal complex. This week Dognon et al. discuss the possibility of 32-electron organometallic complexes.[JACS] In order to reach 32-electrons, f-orbital participation is essential. Below is a picture of a hypothetical organometallic complex with 28 carbons in a cage around an actinide element.

An@C28

 

Although these systems are not new, as the Smalley group made U@C28 in the gas-phase in ’92,[Science] Dognon et al. examine a series of these systems for different actinides. The major conclusion is that the plutonium system is theoretically predicted to have the largest bonding energy for its Pu4+@C28 complex. Since fullerenes and the intercalation of metals often only need heat to be synthesized, I wouldn’t be surprised if these complexes have already been made but missed as impurities and byproducts.

Link to paper: A Predicted Organometallic Series Following a 32-Electron Principle: An@C28 (An = Th, Pa+, U2+, Pu4+)

Update 1: Jyllian Kemsley also covered it at C&EN — Stable Caged Actinides Proposed(subscription)

Mitch