I missed it
I must have blinked
Physicists have whittled down the world’s shortest laser pulse to just 43 attoseconds (4.3 x 10-17 seconds), fast enough to observe electrons moving during chemical reactions in slow motion for the first time. The blip “is the shortest controlled event that has ever been created by humans,” the boffins bragged. The …
but I guess one could "locate" the electrons in order to randomize their motion or vise versa. I find it hard to imagine detecting the motion of an electron in a molecule and being able to react fast enough to affect a chemical reaction. Do they just disturb a known resonance by observing electrons in order to change a bond? In any case I hope this research results in more than a flash in the pan.
"I find it hard to imagine detecting the motion of an electron in a molecule and being able to react fast enough to affect a chemical reaction."
The idea is to play with the light electric field (e.g., randomly manipulate it) until it drives the reaction in the right direction. Google 'coherent control' for the details. It didn't work with nanosecond, picosecond, or femtoseond pulses. But t̶h̶i̶r̶d̶ fourth time is a charm, as they say :).
Science: Scientists made very short, weak X-ray laser pulses
- Pulse duration: 43e-18 s (43 as)
- Energy: some 100 +/- 100 eV
- Applications: To be found (see outlook of their paper)
Hype: We can make molecular movies, we can see bio/chemical reactions in real time.
- "... directly observe how the electrons in molecules of [phosphorus and sulphur] – both elements common in biochemical reactions move when excited." Only they didn't make a single experiment on a molecule, nor on phosphorous or sulfur, nor on anything biological. Their outlook talks about a bright future, where angels sing and attoseconds dance --maybe this got mixed up a bit in the press release.
- "...the researchers effectively found a better way to snapshot chemical reactions ..."
Chemical reactions involve atoms moving. the fastest atom motion is in the hydrogen molecule with some 8 fs ground state motion period and a ground state vibrational energy of 1/2* 4166 cm-1. Their photons have an energy of some 100 eV = 8e6 cm-1 and an energy uncertainty of some 8e6 cm-1. Using these photons to see chemical motion is a bit like using a cargo ship to feel the shape of a mussel stuck to the pier.
- "The team also hopes that the ultra-mega-super-fast laser can be used to manipulate chemical reactions as well as observing them." Photons of 100 eV energy are soft x-rays and are ionizing radiation. Common bio/chemical reactions involve energies in the range of 1 eV or below. Again a bit of a mismatch, akin to controlling the motion of a snail by running it over with your car. But then, this claim has been made for every new light source in the last 100 years, so I guess it would be odd to leave it out.
Don't get me wrong, those scientists set up a great experiment and they'll eventually find a use for their laser. But why do those press releases have to claim the suspension of all physical laws and free doughnuts for everyone?
"Don't get me wrong, those scientists set up a great experiment and they'll eventually find a use for their laser. But why do those press releases have to claim the suspension of all physical laws and free doughnuts for everyone?"
Yes, there may be a little of the usual blarney in the press release, but the first application mentioned in the article refers to the development more efficient solar panels.
One of the best models we have for capturing photon energy is the chloroplast, and the secret to its relatively good efficiency is the way that an excited electron (exciton) travels extremely fast from a chlorophyll molecule to the chloroplast reaction centre, where its energy is captured to produce ATP to fuel subsequent chemical reactions.
The longer the exciton takes to reach the reaction centre, the more energy it loses before ATP is produced and the efficiency of energy capture falls off dramatically, so being able to study excitons' movement using very short laser pulses may help us to drastically improve the efficiency of similar processes occurring in a solar panel.
"One of the best models we have for capturing photon energy is the chloroplast, and the secret to its relatively good efficiency"
With just the slight issue that chloroplasts don't have relatively good efficiency at all. The absolute highest efficiency estimate for biological photosynthesis is about 6%. Depending on what plant you look at and exactly how you define efficiency (ie. just the actual photo capture reaction or the whole process surrounding it), it can be as low as 0.1%. Meanwhile standard commercially available photovoltaic cells are generally in the region of 15-20%, while various research cells have reached nearly 50%. That doesn't mean there's nothing that we can learn from biological processes, but the idea that they're some amazing model we should seek to replicate is just nonsense; as far as efficiency is concerned we're at least an order of magnitude ahead already.
Re-engineering chlorophyll could make for algae that produces biofuel faster/cheaper. Who needs photocells? I want my internal combustion engines to continue running inexpensively!
More to the point, it should be possible to produce food better/faster with a given amount of sunlight than we can manage now. Feed the world with bioengineering, and then on to Mars!
So now I've pissed off both the anti-carbon and the anti-GMO crowd. Life is good :-)
Jake, you could GM more efficient chlorophyll, in fact it has already been done but you're never going to be able to grow biofuels in a carbon netural or carbon negative way on a scale needed to replace fossiel fuels. We don't really need bioengineering to feed the world. We have the technology to do that already and more techonology is coming along (such as hydroponics, vertical farms, on lad aquaculutre etc) to do it even better. It's our economic model that is the root of so many of our problems.
Does any of all this have an application that could be put towards terra-forming? i.e. such as gas converters to clean up the air balance a bit (co2-> o2 for example, extracting the carbon in solid form).
Having said that, The Earth is a pretty big engine, so doing something on a scale that is relevant is most likely out of our reach until the human race faces extinction unless it does something.
" It's our economic model that is the root of so many of our problems."
I'm more of the opinion that it's overpopulation. Fewer people = less of a problem feeding them or providing them with other forms of energy. Don't mention that to business people or governments though - they don't care about the long-term or the welfare of individuals.
.......come here for the IT, stay for the postgrad physics/chemistry/biology/astronomy/mathematics/accountancy/aerodynamics/comedy discourse.
Seriously, I am amazed that The Gruniad or similar has never done a deal to include El Reg stories and comments say 12 hours after they're posted here, the quality of the writing and level of understanding of the assorted subject matters is excellent. Of course the Headlines editor is just jam on the bun.
Keep up the good work.
That is (potentially) a quite phenomenal degree of control over a chemical reaction.
Of course doing it to individual molecules, instead of what would normally be a cloud of them, is going to almost equally difficult.
So very high order boffinry.
"Of course doing it to individual molecules, instead of what would normally be a cloud of them, is going to almost equally difficult."
Amazon'll be offering it next week then.
The chemistry of things (TM) What's not to fear?
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