Pics of Individual atoms

[losfomot]

I did not want to continue with this discussion in YT's thread, so I started a new one...

 

http://www.almaden.ibm.com/vis/stm/gallery.html

 

Xenon atoms on Nickel substrate :

 

Iron atoms on Copper (a Quantum Corral) :

 

 

Single Electron Spin measurement by Rugar et al' date=' IBM-Almaden

http://www.almaden.ibm.com/st/nanoscale_science/asms/mrfm/

 

The Nature article :

http://domino.research.ibm.com/comm/pr.nsf/pages/rscd.nanoscale-picb.html/$FILE/single%20spin%20MRFM%20Nature%20article.pdf[/quote']

 

Everyone is pretty adamant that these are 'pretty much' photos of atoms. So, the majority of atoms appear to be cone shaped, is that right?

 

Is this the actual SHAPE of the atom, or is it an outer boundary created by the electrons in the atom?

 

The site itself talks about the artist's this and that, rather than going into scientific detail about the images, so it is difficult to truly tell what it is I'm seeing.

[Daecon]

Hmm... it seems to me, to be merely a 3D representation of the kind of graph where you scan for traces of specific atoms, which is making the "spiked" effect, rather than a representation of the boundary/shape of the atom itself.

 

I forget what the name of that type of graph is called (I know, I'm stupid) but it just registeres a "bumb" when it detects the presence of a particular type of atom, y'know?

[ed84c]

If you see on the first one the EM is only detecting the Xe atoms, otherwise they should have the same depth of the Ni atoms.

[timo]

So, the majority of atoms appear to be cone shaped, is that right?

I think that your pictures are 2D with the measured intensity plotted as height. So the answer would be "no". As another matter of fact you have to keep in mind that these are not pictures of free atoms but of bound ones.

Is this the actual SHAPE of the atom, or is it an outer boundary created by the electrons in the atom?

What´s the difference between those two things?

 

On the scale we seem to be talking about there is no such thing as a sharp boundary of an atom as you might guess from the pictures yourself.

[MetaFrizzics]

You can actually see an atom. First you trap it in an EM field.

Then you excite it and make it release light.

You don't need a super-microscope or special eyeballs.

You just need to think outside of the box.

A snapshot of this would be a TRUE picture of an atom.

[DQW]

You can actually see an atom. First you trap it in an EM field.

Pray, tell me how you isolate and trap a single atom (and confine it to a spatial width that is about the size of the atom itself) ? And how would you know that you have only one atom ?

Then you excite it and make it release light.

What modes are you exciting here, and how do you go about this excitation process ?

You don't need a super-microscope or special eyeballs.

Electronic transitions are typically in the far UV. If you want to see photons that are spit out by electronic transitions, you better get yourself a new pair of special eyeballs.

You just need to think outside of the box.

The box called 'reality' ?

A snapshot of this would be a TRUE picture of an atom.

Let's say you have this atom that you have somehow isolated, trapped and excited. This atom is slowly spitting photons radially outwards. You want to pass these photons through a lens that focuses them onto some kind of photographic surface (that I shall call the 'film'). At a magnification of 1, all the photons end up exposing the same molecule on the film. That'll achieve nothing. Even if you can ensure that no other molecule on the film gets exposed by thermal photons from the enclosure that houses the trapped atom, or even by thermal excitations at the ambient temperature (remember that "exposure" is simply a chemical reaction that is highly susceptible to photo-activation, so the assumptions made are already unachievable), what you end up with is a picture where 1 molecule is different from the rest. Surely, you can't see this one-molecule-difference any better than you could see the trapped atom with your naked eye. So, you must have some large magnification introduced by some lens assembly, so that a macroscopic number of molecules are exposed by these photons. To be able to see something, this magnification would have to be at least something of the order of several million (that way you an image that's a few millimeters wide). Hmm... what device achieves such large magnifications ? I wonder...

[Yggdrasil]

There was actually an article on this in Scientific American recently (in the Apr 2005 issue, check it out on pg 26-27). The researchers actually don't look at the atom, but rather image the wavefunctions of the electron orbitals around the atom. They do this by using a laser pulse to get an electron in a state which is semi-in-place and semi-excited. Apparently, this will cause the electron to emit a plane wave which interferes with the original wave function of the electron. The interference patern causes an emission of UV radiation which the researchers can examine to determine the wave function of the electron.

 

Apparently, this technique is so powerful that it may be able to image molecules during chemical reactions. Very exciting from a chemist's point of view.

[MetaFrizzics]

Yggdrasil: Thank you for confirming my claim. As a matter of fact this has been done over and over again. I first heard about it many years ago.

 

'Seeing' is receiving light from an object into the retina.

 

'Plotting' is taking measurements and making a graph.

 

You can indeed see a single atom or even electron.

It may not look like much more than a magic star, glowing and pulsing,

but nothing beats the thrill of knowing you are actually seeing it,

and not through a microscope, scanner, or 'interpreter'.

[ydoaPs]

i still don't understand the difference between looking at it with photons and looking at it with electrons. btw, with that technique, you can't see it either, it is UV, not visible spectrum.

[MetaFrizzics]

Pray' date=' tell me how you isolate and trap a single atom (and confine it to a spatial width that is about the size of the atom itself) ? And how would you know that you have only one atom ?

What modes are you exciting here, and how do you go about this excitation process ?

Electronic transitions are typically in the far UV. If you want to see photons that are spit out by electronic transitions, you better get yourself a new pair of special eyeballs.

The box called 'reality' ? ... I wonder...[/quote']

 

I hate to pull you on the carpet for this, but it is so cool, I think people should know about it:

 

"We never experiment with just one electron or atom...any more than we can raise Ichthyosauria in the zoo." -Erwin Schroedinger, 1952

"Here, right now, in a little cylindrical domain... in the center of our Penning Trap resides positron Priscilla, who has been giving spontaneous and command performances of her quantum jump ballets for the last three months." - Announcement from Hans Dehmelt's lab in Seattle, 1984

 

"In 1979 in Heidelberg' date=' Germany, Dr. Werner Neuhauser looked up from the eyepiece of a low-power microscope and fancied he heard the ghost of Mach whispering: "Now I believe in atoms!". Neuhauser had just glimpsed what appeared to be a bright blue star floating in the void: it was a single barium ion, caught in an electromagnetic trap and flourescing in a laser beam. Thus transpired the first observation of an isolated atom using a lens; soon one would be glimpsed with the naked eye as well. (The common claim that no one would ever see an atom with the naked eye was an error, assuming smallness was the important issue. In fact, brightness and isolation from other atoms are what matters.)"

................................................. The Infamous Boundary by D. Wick pg 137ff [/quote']

[ydoaPs]

quotes are not evidence...besides, that quote was from 1952, so it is probably outdated

[MetaFrizzics]

quotes are not evidence...besides, that quote was from 1952, so it is probably outdated

Did you actually read my post?

The 1952 quote by Schroedinger was AGAINST seeing an atom, and he was proved wrong. Read what follows: How can historical events be 'outdated'?

[ydoaPs]

then why did you put the quote?

[AzurePhoenix]

I think it was actually supposed to be a timeline, you know, like the History of Mankind's Quest for the Atom

[MetaFrizzics]

This is from another thread here:

In case someone missed it, they have apparently imaged an electron orbit too:

 

http://www.nrc-cnrc.gc.ca/highlights/0501electronimaging_e.html

[DQW]

deleted...no patience now for long post