I was listening to a cassette tape of a lecture that Feynman gave at
CalTech. He was discussing potential energy and forces. He made an
interesting comment which I think is a good summary statement:
"The idea of force is not one which goes well into Quantum Mechanics, but
the idea of energy is just ideal in the Quantum Mechanics....Very rarely
[in a QM Book] do you see a curve for the force between two molecules."
Steven T. Ratliff
Professor of Physics
Northwestern College
3003 Snelling Ave. N.
St. Paul, MN 55113-1598
U. S. A.