Researchers devise a means to control chemical reactions in individual atoms

Jul 25, 2012 by Bob Yirka report

(Phys.org) -- In the early days of chemistry, finding out what happened when two or more chemicals were mixed together led to the development of all manner of new materials and to deriving useful events, such as the production of heat or light, or things exploding. As the science progressed however, researchers found they wanted to know more about what really goes on when chemicals react, but were unable to find out due to the massive number of interactions that occur during even the most ordinary chemical reactions. Nowadays, researchers want to delve even deeper, to discover what goes on at the quantum level. To that end, a team working at the Cavendish laboratory in Cambridge, UK has developed a way to monitor and control one of the most basic chemical reactions, the meeting of two dissimilar individual atoms. In their paper published in Nature Physics they describe how they were able to do so by setting up special experiments in a cold environment using a laser.

Under normal conditions, when two atoms meet, usually nothing happens. There is no attraction force between the two thus no reason for them to interact. When one or both are ions, things are different of course as the ions have either more or less electrons than stable atoms, causing them to have an electric charge. It was this property that the team used when setting up their experiments, which were meant to serve as an observational study, not to create something new, to see what happens at the quantum level.

In their experiments, the team used a magnetic field to isolate two different types of atoms, a ion and a neutral rubidium, in a very to slow things down. But prior to pushing them together with a laser, they first excited the ytterbium ion by shooting it with to inject it, so to speak with . That energy they noted, could result in movement due to heat ejection or in the production of photons.

Next, they ran two different types of experiments. In the first, they turned off the lights and watched as the two atoms eventually came near one another, to see if the interaction between the two would result in the release of photons, i.e. light. It did not, instead, it resulted in both atoms moving around in the trap at higher speeds.

In the second experiment they used a laser to push the energized ion towards the neutral atom and found that in some, but not all cases, an ion was exchanged, causing the ytterbium atom to become neutral and the to become ionized; a clear example of a controlled chemical reaction between just two atoms. The researchers noted that the spin state of the atoms made a difference in the outcome of the reaction, meaning that the atomic nucleus of the atom had an impact, which goes counter to conventional thinking.

The experiments and results the researchers achieved show that chemical reactions can not only be studied at the , but controlled as well, a finding that will likely have a major impact on both chemistry and physics research going forward.

Explore further: Cooling with molecules

More information: Controlling chemical reactions of a single particle, Nature Physics (2012) doi:10.1038/nphys2373

Abstract
Traditionally, chemical reactions have been investigated by tuning thermodynamic parameters, such as temperature or pressure. More recently, laser or magnetic field control methods have emerged to provide new experimental possibilities, in particular in the realm of cold collisions. The control of reaction pathways is also a critical component to implement molecular quantum information processing. For these studies, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achieving quantum-limited control of chemical reactions and indicate limits for buffer-gas cooling of single-ion clocks.

via Arstechnica

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Lurker2358
5 / 5 (1) Jul 25, 2012
The researchers noted that the spin state of the atoms made a difference in the outcome of the reaction, meaning that the atomic nucleus of the atom had an impact, which goes counter to conventional thinking.


Should have expected something like this. After all, researchers are already developing macroscopic tools which work on spin currents, such as racetrack memory, which of course involves and influences electrons and their spin states for memory purposes.

The spin state of the nucleus, and even the individual electrons, should therefore offer a bias in the chemical behavior by producing an attractive or repulsive force which stacks constructively or destructively with the electric charge.

This would suggest that you might be able to produce interesting properties in some chemical reactions by applying a magnetic field during the process.

Maybe this could control right handed or left handed chirality, or maybe it could act as a catalyst to make reactions more efficient.
Husky
not rated yet Jul 25, 2012
it would be great if a machine was developed that could quantum weld atoms with laser, by just putting the minimum energy required in the tiny spot, one would need arrays of quantum dot or nanocone lasers to scale this up to production level.
Lurker2358
5 / 5 (1) Jul 25, 2012
More research please.

This should prove very useful in development of many things, perhaps new cleaning agents, nanomachines, and maybe atomic transistors.

If the spin state modifies chemical behavior, then maybe a magnetic field or an electric current could prevent some forms of corrosion in materials by inhibiting reactions. Although electroplating has been used to encourage bonding of metals for possible 3 millennia now, perhaps the reverse could be achieved as well through further research and manipulation. If such is the case, it would prove very useful in bridges and other structures with high maintenance costs, and perhaps shipping, metal roofing, or even automobiles.

We know how to produce both microscopic and macroscopic biases in the spin state through electromagnetism, we do it all the time in computers.
antialias_physorg
not rated yet Jul 25, 2012
ed to the development of all manner of new materials and to deriving useful events, such as the production of heat or light, or things exploding
...and usually all three.

Should have expected something like this. After all, researchers are already developing macroscopic tools which work on spin currents, such as racetrack memory, which of course involves and influences electrons and their spin states for memory purposes.

They say the spin of the NUCLEAUS has an effect. That the electrons have an effect was known (chemical bonds are electrons shared between atoms) - but that spins of the protons (and the neutrons?) in the nucleus would influence whether or not such an exchange takes place wasn't known or suspected.

The aim of this has to be to figure out a way to build molecules from the ground up. Atomic level 3D printing. That would be so neat.
Lurker2358
not rated yet Jul 25, 2012
They say the spin of the NUCLEAUS has an effect.


Yes, I got that. It should have been suspected, since even though the spin of the nucleus is relatively far away from the electrons, it should exert a net, non-zero force on the electrons, causing a bias of sorts.

The aim of this has to be to figure out a way to build molecules from the ground up. Atomic level 3D printing. That would be so neat.


Obviously, and this would hopefully include an understanding of chirality in molecules, as well as atomic transistors and nano-machines.

The ability to build both the left-handed and right-handed versions of molecules will undoubtedly become necessary at some scale of development of advanced devices and materials. Regardless of the spin effect, this research should be important to that end either way.

I was just making the observation that there "may" be a connection between this spin effect and the chirality, due to spin bias, or there "may" not be.
Eoprime
5 / 5 (2) Jul 25, 2012
"In the second experiment they used a laser to push the energized ion towards the neutral atom and found that in some, but not all cases, an ion was exchanged, causing the ytterbium atom to become neutral and the rubidium to become ionized..."

Find the fault and win a cake!
Lurker2358
not rated yet Jul 25, 2012
"In the second experiment they used a laser to push the energized ion towards the neutral atom and found that in some, but not all cases, an ion was exchanged, causing the ytterbium atom to become neutral and the rubidium to become ionized..."

Find the fault and win a cake!


Yes, I noticed it earlier, but made no comment.

The author accidentally used the word "Ion" in the phrase "an ion was exchanged"; clearly the correct word should be "electron".
antialias_physorg
not rated yet Jul 25, 2012
The ability to build both the left-handed and right-handed versions of molecules will undoubtedly become necessary at some scale

We can already do that. Every protein, amino acid or whatever other organic molecule we produce artificially in the lab (without using living things as a factory, that is) comes out 50/50 in terms of chirality (mostly called the L- and D- variants). So there doesn't seem to be an effect of spin on chirality.

Chirality in proteins of living organisms is actually THE smoking gun that all life shares a common ancestor.
Lurker2358
not rated yet Jul 25, 2012
We can already do that. Every protein, amino acid or whatever other organic molecule we produce artificially in the lab (without using living things as a factory, that is) comes out 50/50 in terms of chirality (mostly called the L- and D- variants). So there doesn't seem to be an effect of spin on chirality.

Chirality in proteins of living organisms is actually THE smoking gun that all life shares a common ancestor.


50/50 isn't controlled.

What if say, a drug is more effective if it is 100% left handed or 100% right handed? Then it would be useful to develop a means of producing such a drug at the nanoscale in such a way that only the more effective version is produced.

Also, If you want to build a truly symmetrical molecular machine, you need the right handed molecular component on one side and the left handed on the other side, etc.

Well, organisms one handed, but then again, organisms are not perfectly symmetrical.
Lurker2358
not rated yet Jul 25, 2012
Chirality in proteins of living organisms is actually THE smoking gun that all life shares a common ancestor.


That's conjecture.

Chirality bias exists in non-living systems in the universe, such as galaxy rotation and even planetary systems. Most of the planets in the solar system rotate the same way, and so do most of the moons. Spiral galaxy rotation in the universe biased based on the hemisphere of the Earth!

I need a citation for that last statement, so here it is:

http://www.techno...orthern/

1, why a galaxy bias at all?

2, why a galaxy bias that appears centered on the Earth observer?!? A question not even asked by the author!

Now I'm on a rabbit trail, but I said that to say this, the bias in life's molecules in no way supports a common ancestry argument. Maybe left handed molecules are just "better" for some reason we don't know yet.
Lurker2358
not rated yet Jul 25, 2012
Just to give another example fo some screwed up chirality physics.

the planets in the solar system all rotate prograde except Venus and Uranus.

However, in a semi-uniform rotating disk, the RETROGRADE rotation is the preferred condition of any clumps or planetesmals that should form, because the matter from the "inside" edge of the clump must be moving faster than the matter from the "outside" edge, because it takes more velocity to maintain a stable orbit.

But in the real solar system there is a pro-grade bias, with 6 of the 8 major planets, and most of the moons, all rotating prograde.

Galaxy bias? That's not a selective bias, that's a creation bias, since there has been no "selection" since the creative event, there's no force large enough or biased enough to have "selected" galaxies since creation, and even if there was, what would it be and where are the remnants of those other galaxies, if they ever existed?
Isaacsname
not rated yet Jul 28, 2012
More research please.

This should prove very useful in development of many things, perhaps new cleaning agents, nanomachines, and maybe atomic transistors.

If the spin state modifies chemical behavior, then maybe a magnetic field or an electric current could prevent some forms of corrosion in materials by inhibiting reactions. Although electroplating has been used to encourage bonding of metals for possible 3 millennia now, perhaps the reverse could be achieved as well through further research and manipulation. If such is the case, it would prove very useful in bridges and other structures with high maintenance costs, and perhaps shipping, metal roofing, or even automobiles.

We know how to produce both microscopic and macroscopic biases in the spin state through electromagnetism, we do it all the time in computers.


You mean similar to cathodic protection ?