[jeffwass]

When I studied undergraduate quantum mechanics (physics dept, many years ago) one of our homework problems involved oscillation of the ammonia atom. Ie, the three hydrogen atoms form a triangle, and the nitrogen atom is in a superposition of states above or below the hydrogen plane.

Iirc, given some estimate of the relative potential energy barrier formed by the hydrogen atoms, we showed that the nitrogen atom would effectively oscillate between the up and down states and calculated the frequency of oscillation.