Field of Science

Showing posts with label atoms. Show all posts
Showing posts with label atoms. Show all posts

First pentacene, now this

It just seems to get better. Last week a stellar AFM picture of pentacene showing the molecules with unprecedented resolution made the news. This week the picture seems to get even deeper

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The pictures, soon to be published in the journal Physical Review B, show the detailed images of a single carbon atom's electron cloud, taken by Ukrainian researchers at the Kharkov Institute for Physics and Technology in Kharkov, Ukraine.

This is the first time scientists have been able to see an atom's internal structure directly. Since the early 1980s, researchers have been able to map out a material's atomic structure in a mathematical sense, using imaging techniques.

Quantum mechanics states that an electron doesn't exist as a single point, but spreads around the nucleus in a cloud known as an orbital. The soft blue spheres and split clouds seen in the images show two arrangements of the electrons in their orbitals in a carbon atom. The structures verify illustrations seen in thousands of chemistry books because they match established quantum mechanical predictions.

David Goldhaber-Gordon, a physics professor at Stanford University in California, called the research remarkable.

"One of the advantages [of this technique] is that it's visceral," he said. "As humans we're used to looking at images in real space, like photographs, and we can internalize things in real space more easily and quickly, especially people who are less deep in the physics."

To create these images, the researchers used a field-emission electron microscope, or FEEM. They placed a rigid chain of carbon atoms, just tens of atoms long, in a vacuum chamber and streamed 425 volts through the sample. The atom at the tip of the chain emitted electrons onto a surrounding phosphor screen, rendering an image of the electron cloud around the nucleus.
Whenever I see something like this I always wonder how utterly exhilarated and astonished Dalton, Boltzmann, Maxwell, Heisenberg, Bohr, Einstein and others would have been if they had seen all this. I remember that Stuart Schreiber's life trajectory was set when he saw orbitals first presented as gorgeous lobes in class. The Schreibers of the twenty-first century could have much more to be excited about. Man's dominion over the understanding and manipulation of matter sometimes seems almost mythical.

Update: After thinking about this a little more and looking at the comment in the comment section my exhilartion has been tempered by skepticism (for a good scientist it should ideally be the other way around...I am still learning). The orbitals look perfect, and I would be interested in knowing what kind of actual techniques they use to process the initial raw data into this finished image. Plus, what about sp3 hybridization?