The thing about that article that confuses the living fuck out of me is that in 1992, when I was in Chemistry, our teacher handed out a news article that talked about this very thing. I remember it clearly -- scientists had "photographed" an atom with a tunnelling microscope. And now I want to know what the hell I was reading, because I thought this had been done already.
What maskedretriever said---in 1992, scanning tunneling microscopy was sort of new, and what it could detect, from a distance (relatively speaking "a distance") was the presence of available states for an electron to tunnel to/from the probe tip to the atom. Handwaving frantically, there are more available states at a given energy near an atom, so if you set the tunnelling electron's energy to something near the available energy level the atoms you're looking at provide, you'll be able to detect where the atom (and the next atom, and the next atom) is in the sample.
But within those states themselves, electrons don't just whip around in a sphere around the atom. (Except in some of them, the lowest energy state being one such.) Some of the states have significantly different shapes; the electron is more likely to be here or here around the atom than there or there. Have a look at this picture. Those pictures are obtained by solving Schroedinger's Equation for the hydrogen atom.
Look at the second row, showing the possible electron density shapes for electrons with quantum number 2, then look at the pictures at the link in the post again.
The outermost electrons for carbon atoms have the quantum number 2.
That's why I got tears in my eyes when I saw the pictures. That there is a blasted probability density function posing for a picture. It's mathematics become real.
...I think I should rewrite and post this on electrons_write too, shouldn't I. Tomorrow.
Believe it or not, because of the way some bonding occurs due to electron orbital shapes (especially covalent bonds), we had to learn the SPDF orbitals (and I had to do some pointless memorizing) in high school Chemistry. :O
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(no subject)
Date: 2009-09-17 04:11 pm (UTC)(no subject)
Date: 2009-09-17 04:49 pm (UTC)Now you have a set of bumps that are definitely caused by lobes of the electron clouds. Qualitatively higher resolution, is what's new.
(no subject)
Date: 2009-09-17 05:50 pm (UTC)But within those states themselves, electrons don't just whip around in a sphere around the atom. (Except in some of them, the lowest energy state being one such.) Some of the states have significantly different shapes; the electron is more likely to be here or here around the atom than there or there. Have a look at this picture. Those pictures are obtained by solving Schroedinger's Equation for the hydrogen atom.
Look at the second row, showing the possible electron density shapes for electrons with quantum number 2, then look at the pictures at the link in the post again.
The outermost electrons for carbon atoms have the quantum number 2.
That's why I got tears in my eyes when I saw the pictures. That there is a blasted probability density function posing for a picture. It's mathematics become real.
...I think I should rewrite and post this on
(no subject)
Date: 2009-09-17 06:06 pm (UTC)(no subject)
Date: 2009-09-18 03:39 am (UTC)(no subject)
Date: 2009-09-17 04:13 pm (UTC)(no subject)
Date: 2009-09-17 08:58 pm (UTC)