Can I ``See'' inside an Atom

To see inside an atom, we must use light with a wavelength smaller than the size of the atom. With normal light, once a surface is polished down to the .25 micron level, it looks shiny. You can no longer see defects. So to see inside the atom, we would need light with \bgroup\color{black}$\lambda={h\over p}=0.1$\egroup Å.

p&=&{2\pi\hbar \over 0.1}\\
pc&=&{2\pi\hbar c \over 0.1}={2\pi 1973\over 0.1}=120000 \mathrm{eV}\\

This is more than enough kinetic energy to blow the atom apart. You can't ``see'' inside.

A similar calculation can be made with the uncertainty principle.

\Delta p\Delta x\geq {\hbar\over 2}\\
\Delta(pc)\Delta x\geq ...
...\Delta x}\\
E_\gamma \geq {\hbar c\over 2(0.1 \AA)}=10000 eV\\

The binding energy is 13 eV, so this will still blow it apart.

So we can't ``watch'' the inside of an atom.

We can probe atoms with high energy photons (for example). These will blow the atoms apart, but we can use many atoms of the same kind. We learn about the internal structure of the atoms by scattering particles off them, blowing them apart.

Jim Branson 2013-04-22