Lecture IV: Atoms & Molecules

Take home points on atoms and molecules.

  1. Atoms and Molecules exist -- subnanometer scale.
  2. Molecules are bound atoms.
  3. Energy can be extracted from molecules (tomorrow).

Scanning tunneling microscope allowed seeing atoms well. [1986 Nobel Prize: Binnig and Rohrer]
Current flow depends on tip-atom distance. Picture contrast is measure of current flow.
7 x 7 Si

stm diagram

Forming a molecule on a surface

Fe = iron atom on silver surface (Ag);
CO - for carbon-monoxide on Ag.
(A) Tip induces detachment of CO and bonding to tip;
(B) tip with CO move toward Fd atom on surface
(C) tip reverses process, detaching CO to surface; (D) single Fe-CO bond formed.
(A) Five Fe atoms and five CO molecules on Ag surface.
(B) formation of Fe-CO shown in whole figure above.
(C) Another Fe-CO formed.
(D) Second CO moved to Fe-CO to form Fe(CO)2.
Molecule. etc.
Oxygen molecule: what is it?
Carbon dioxide
Nitrogen dioxide
ethane Ethane
Chemist view of hydrogen and oxygen forming wather.
Propane combusting with oxygen to from carbon dioxide, water, heat and light

To cite this page:
Lecture IV: Atoms and Molecules
[Sunday, 21-Oct-2018 20:01:50 EDT]
Edited by: wilkins@mps.ohio-state.edu on Wednesday, 24-Sep-2008 17:53:53 EDT