Double Minima, Earnshaw's Theorem and Plum-Puddings
Richard M. Colgate Professor of Chemistry
This lecture explores the structural equilibrium of molecules like ozone using double-well potentials. It then elucidates Earnshaw's Theorem regarding the instability of electrostatic equilibria and examines J. J. Thomson's plum-pudding atomic model.
Freshman Organic Chemistry (CHEM 125)
Continuing the discussion of Lewis structures and chemical forces from the previous lecture, Professor McBride introduces the double-well potential of the ozone molecule and its structural equilibrium. The inability for inverse-square force laws to account for stable arrangements of charged particles is prescribed by Earnshaw's Theorem, which may be visualized by means of lines of force. J.J. Thomson circumvented Earnshaw's prohibition on structure by postulating a "plum-pudding" atom. When Rutherford showed that the nucleus was a point, Thomson had to conclude that Coulomb's law was invalid at small distances.
Force Laws, Lewis Structures and Resonance
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