Cornell's Duffield Hall has acquired a new electron microscope that is enabling scientists to see individual atoms in color for the very first time. While old electron microscopes can be compared to black and white cameras, this new scanning transmission electron microscope uses a new aberration-correction technology that is both more intense and allows for faster imaging speed. "The method also can show how atoms are bonded to one another in a crystal, because the bonding creates small shifts in the energy signatures. In earlier STEMs, many electrons from the beam, including those with changed energies, were scattered at wide angles by simple collisions with atoms. The new STEM includes magnetic lenses that collect emerging electrons over a wider angle. Previously, Silcox said, about 8 percent of the emerging electrons were collected, but the new detector collects about 80 percent, allowing more accurate readings of the small changes in energy levels that reveal bonding between atoms."
Using false-color in an image is certainly not the innovation. What is innovative is their use of corrective optics to achieve much higher signal (100-fold increase compared to conventional techniques), and the integration of energy-loss spectroscopy. This means that for each pixel in the image, they can determine what kind of atom is being measured. So they can generate false-color maps of atomic identity. Most electron microscopes simply measure electron density: you can guess which element is which based on density, but there can be ambiguities. Some microscopes include detectors for determining what elements are present, but not with high spatial resolution. This new refinement allows precise maps where individual atoms can be both localized, and elementally identified.
The image they show is impressive when you consider that each blob of color is actually an individual atom, and that they've identified exactly what kind of atom is at each position. In this case they were using it to analyze interdiffusion of atoms at an interface. As nanotechnology becomes more and more 'real' you can imagine how useful it will be to image nano-objects with atomic resolution and elemental discrimination.
Not to get too technical here, but each blob is actually a column of atoms, as the specimen is wedge-shaped and certainly more than one atomic layer thick.
Electron energy-loss spectroscopy (EELS) has been combined with STEM imaging for several years at least, allowing similar sorts of images to be synthesized. The major contribution of this work is that they've modified the optics so that, even at 0.5 angstrom beam widths (and hence pixel sizes), they still get enough signal to the EELS detector to allow for EELS mapping and spectra acquisition for each of those pixels, giving direct bonding information about the particular portions of atoms probed by the beam. That means that the researchers can tell the difference between titanium atomic columns at different locations within the crystal, depending on the other atoms surrounding them.
Well, I suppose I did end up getting too technical.
IAATEL (I am a transmission electron microscopist)
Using false-color in an image is certainly not the innovation. What is innovative is their use of corrective optics to achieve much higher signal (100-fold increase compared to conventional techniques), and the integration of energy-loss spectroscopy. This means that for each pixel in the image, they can determine what kind of atom is being measured.
Almost. Energy-loss spectroscopy in SEMs isn't new. (And I don't think it's new in STEMs, either, AFAIK.) The innovation is in the corrective optics, as you
This means that for each pixel in the image, they can determine what kind of atom is being measured. So they can generate false-color maps of atomic identity.
That's interesting. I guess this microscope will have lots of applications. At first thought - in semiconductors production, carbon allotropes and God knows where else.
Just look at the images in the article; you can clearly distinguish lanthanum from titanium, manganese, and manganese-lanthanum. From that list alone the mind boggles with potential applications.
The color is based on the energy of the electrons, just like photon "color" is based on the energy of individual photons. The microscope is "color" because it can record the energy of the electrons as well as their density. Thus it is "color" just as much as your eyes - which measure photon energy (cone cells of 2 to 3 or in some cases 4 types) as well as photon density (rod cells). Note that your cone cells require more light to get a color signal. In dim light, you see black and white via your rod cel
Not necessarily, one way that atoms can emit light is if you bump its electrons in to a higher orbit with energy, when they return to their natural state the will emit energy sometimes in the form of visible light. This is how things that glow when exposed to ultraviolet light work. At least if I remeber my high school chemistry correctly.
The summary didn't say, but the colors MUST be false color, since atoms are smaller than light wavelengths. But will it allow you to photograph atoms without destroying them? [angryflower.com] (yes the link is humorous, but the question I ask is serious)
There's no milk in my fridge but there are three cats in my house. The cats eat cat food.
What would a single man use milk for? At three dollars a gallon it would be cheaper to feed them gasoline. The only time I have milk in the fridge is when there's a woman living there. And it usually turns into stinky cottage cheese before it's half empty.
Befor you ask, they're my daughter's cats. I got stuck with them when she moved to Ohio with her fiancee.
I doubt that they still survive the process. Organic cells are destroyed due to the direct irradiation with electrons necessary to produce the "photograph" from the microscope. There are ways around this, such as only focusing the beam on a small part of a specimen or to use a deflection technique that minimally exposes the specimen and deflects the electron beam to the viewing stage. Others are preirradiating the specimens at low doses to stabilize them for increased irradiation. There are other complex techniques outside the realm of my understanding, but I think it still is really tough to preserve organic cells during electron microscopy.
At least not how they are implying. Color as most people think of it has to do with absorbed, reflected and transmitted light. The arrangement of the atoms as much as the atoms themselves affect color. But individual atoms in a crystal don't have color, at least as most people understand. The headline makes it seems like you could come away saying, "So iron atoms really are red..." or something equivalently silly.
I thought it was more to do with the orbitals of the electrons rather than the atomic number of the atom, and the orbitals of the electrons depend on the crystalline arrangement of atoms, and whether they have been ionised or not. Even different ions of the same atom will have a different absorption spectrum [google.com] and emission spectrum [google.com]. So no atom has one unique color, but may have a series of wavelengths of light that it can emit [rochester.edu], which our sight would perceive as a mix of red, green or blue wavelengths [uc.edu],
True, but no one who actually uses one of these would make that mistake. This is pretty cool. Our visual systems are keyed into color differentiation (well, most of us, anyway)-- so it only makes sense to take advantage of that additional visual processing ability to convey more information to the microscopist.
The instrument is a new type of scanning transmission electron microscope (STEM), built by the NION Company of Kirkland, Wash....
I lived there when I was in elementary school. More important, a certain warehouse store has its headquarters there. So I wanna know when I'll be able to pick up one of these STEMs at Costco!
Most of the space occupied by the atom is exactly that, space, nothing more. The electron cloud is a fuzzy region of probability, not a solid thing. The "side" of an atom must be defined by a force, not a particle?
It isn't so much a question of reflection, but more of capturing the excitation of electrons in the atoms that make up the sample by absorbing the irradiated energy. The electrons are excited into higher orbits, which gives off light that the "camera" on this microscope captures and resolves into a cleaner image. That is why organic samples are pretty much goners in EMs. They can't survive that much radiation.
Most of the space occupied by the atom is exactly that, space, nothing more. The electron cloud is a fuzzy region of probability, not a solid thing. The "side" of an atom must be defined by a force, not a particle?
You're right that an atom is mostly empty space, but that doesn't matter. An electron microscope works by shooting a beam of electrons at the sample, and measuring how many of those electrons are transmitted (this is called a TEM; an SEM works differently). The electrons that didn't go straight through the sample were scattered by the atoms of the material. Remember that electrons are charged: as the incident electrons travel through the atoms there will be very strong Coulomb forces. The incident electrons will be repelled by the electrons in the material. This interaction is 'long-range' by subatomic standards: even though the electrons themselves are vanishingly small, the Coulomb interaction distance is quite large.
To a first approximation, 'heavier' atoms (higher atomic number) will scatter electrons more strongly, since they have more electrons. On an electron micrograph, heavy atoms show up as dark (absorbed/scattered alot of electrons), whereas lighter atoms show up as being bright (most electrons were transmitted).
I'm glossing over many details, of course. The important thing to remember is that the incident charged electrons are interacting with the charged electron density surrounding the atoms in the material.
The electron cloud is a fuzzy region of probability, not a solid thing.
Ah, the evil remnants of a flawed basic chemistry and/or atomic physics class.
Just FYI -- not that it relates to this article -- this is wrong. So far as we know, an electron is a point particle, and the electrons in an atom aren't any different from a free electron. They are a collection of little points located at various definite positions. There's no "fuzziness" and they aren't "smeared out" in any sense at all. The "fuzzy cloud"
I'd like to see these atoms rendered in necessarily false color (they're smaller than visible light wavelengths) that is at least the color corresponding to their size. They're smaller than visible wavelengths, but their actual size is a specific fraction of a visible wavelength. Let's see the atoms colored with the color that's a harmonic multiple.
Or maybe the color should be derived from the "texture" of the atom, just like the actual color of macroscopic materials. If a carbon atom has 12 electrons evenly distributed around a sphere in shells (2, 8 and another 2 in valence), let's see it get colored accordingly. Maybe the inner shell's diameter harmonic color in the visible range, divided by 2 and scaled back into the visible, overlapped with the same algorithm for the outer 8 in the second shell, then again for the 2 in the outermost shell.
The point is that these colors can mean something. And since the number and combination of electrons is so important to the characteristics of the electron, as well as offering the femtoscopic equivalent to macroscopic colored surfaces, I'd like to finally see what I've been imagining since high school chemistry class.
Atomic force microscopy (AFM) uses the weak Van der Waals-type interactions between the atoms in a probe, and the surface itself, to measure the locations of atoms. They also developed a qualitative way of identifying the atoms, by measuring the variation of the strength of interaction with probe height. It's not as neat as being able to read real-life energy level information out of atoms, mind you.
Not color, false color. (Score:5, Informative)
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size of atoms wavelength of visible light (Score:2)
Re:Not color, false color. (Score:5, Informative)
The image they show is impressive when you consider that each blob of color is actually an individual atom, and that they've identified exactly what kind of atom is at each position. In this case they were using it to analyze interdiffusion of atoms at an interface. As nanotechnology becomes more and more 'real' you can imagine how useful it will be to image nano-objects with atomic resolution and elemental discrimination.
Parent
Re:Not color, false color. (Score:5, Informative)
Not to get too technical here, but each blob is actually a column of atoms, as the specimen is wedge-shaped and certainly more than one atomic layer thick.
Electron energy-loss spectroscopy (EELS) has been combined with STEM imaging for several years at least, allowing similar sorts of images to be synthesized. The major contribution of this work is that they've modified the optics so that, even at 0.5 angstrom beam widths (and hence pixel sizes), they still get enough signal to the EELS detector to allow for EELS mapping and spectra acquisition for each of those pixels, giving direct bonding information about the particular portions of atoms probed by the beam. That means that the researchers can tell the difference between titanium atomic columns at different locations within the crystal, depending on the other atoms surrounding them.
Well, I suppose I did end up getting too technical.
IAATEL (I am a transmission electron microscopist)
Parent
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Almost. Energy-loss spectroscopy in SEMs isn't new. (And I don't think it's new in STEMs, either, AFAIK.) The innovation is in the corrective optics, as you
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This means that for each pixel in the image, they can determine what kind of atom is being measured. So they can generate false-color maps of atomic identity.
That's interesting. I guess this microscope will have lots of applications. At first thought - in semiconductors production, carbon allotropes and God knows where else.
Just look at the images in the article; you can clearly distinguish lanthanum from titanium, manganese, and manganese-lanthanum. From that list alone the mind boggles with potential applications.
Actually, it *is* real color. (Score:3, Interesting)
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Ahh Color... (Score:2)
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Schrodinger's Fridge (Score:5, Insightful)
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What would a single man use milk for? At three dollars a gallon it would be cheaper to feed them gasoline. The only time I have milk in the fridge is when there's a woman living there. And it usually turns into stinky cottage cheese before it's half empty.
Befor you ask, they're my daughter's cats. I got stuck with them when she moved to Ohio with her fiancee.
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If you're this guy [olliesbargainoutlet.com], you never have to wonder about that question. (third paragraph)
And for the record, I worked with this guy for a time.
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It is false color, but it wouldn't have to be. It's possible to probe individual atoms with visible light of different wavelengths using STMs.
Re:Schrodinger's Fridge (Score:4, Informative)
Parent
And, Of Course... (Score:2)
Proof at last... (Score:5, Funny)
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So that is why the Hindenburg didn't use Helium.
tHE nEW sKITTLES? (Score:2)
Sorry, couldn't help myself. Marketing controls my mind. And yours.
No native CMY support? (Score:2)
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Atoms don't have color! (Score:5, Insightful)
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Re:Atoms don't have color! (Score:5, Funny)
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absorption spectrum [google.com] and emission spectrum [google.com]. So no atom has one unique color, but may have a series of wavelengths of light that it can emit [rochester.edu], which our sight would perceive as a mix of red, green or blue wavelengths [uc.edu],
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Microsoft Interview (Score:2)
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B: Octarine
Correct answers they don't expect FTW!
Yow! (Score:3, Interesting)
Made in the USA (Score:2)
I lived there when I was in elementary school. More important, a certain warehouse store has its headquarters there. So I wanna know when I'll be able to pick up one of these STEMs at Costco!
What do the electrons "reflect" off of? (Score:2, Insightful)
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Re:What do the electrons "reflect" off of? (Score:5, Informative)
To a first approximation, 'heavier' atoms (higher atomic number) will scatter electrons more strongly, since they have more electrons. On an electron micrograph, heavy atoms show up as dark (absorbed/scattered alot of electrons), whereas lighter atoms show up as being bright (most electrons were transmitted).
I'm glossing over many details, of course. The important thing to remember is that the incident charged electrons are interacting with the charged electron density surrounding the atoms in the material.
Parent
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Ah, the evil remnants of a flawed basic chemistry and/or atomic physics class.
Just FYI -- not that it relates to this article -- this is wrong. So far as we know, an electron is a point particle, and the electrons in an atom aren't any different from a free electron. They are a collection of little points located at various definite positions. There's no "fuzziness" and they aren't "smeared out" in any sense at all. The "fuzzy cloud"
Next up (Score:2)
Real Harmonic Color (Score:4, Interesting)
Or maybe the color should be derived from the "texture" of the atom, just like the actual color of macroscopic materials. If a carbon atom has 12 electrons evenly distributed around a sphere in shells (2, 8 and another 2 in valence), let's see it get colored accordingly. Maybe the inner shell's diameter harmonic color in the visible range, divided by 2 and scaled back into the visible, overlapped with the same algorithm for the outer 8 in the second shell, then again for the 2 in the outermost shell.
The point is that these colors can mean something. And since the number and combination of electrons is so important to the characteristics of the electron, as well as offering the femtoscopic equivalent to macroscopic colored surfaces, I'd like to finally see what I've been imagining since high school chemistry class.
Screenshot (Score:5, Funny)
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There's a nice AFM technique which does this too (Score:2)
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After all, an atom is smaller than a wavelength of visible light, so atoms are quite literally colorless.
Re:This thread is useless without pics! (Score:5, Funny)
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