Top banner   A Really Moving Story  Roald Hoffmann
Chemistry with a Hammer   Figure 1. Argon crashesClick to
Enlarge Image    The Quantum World  Though mysteries remain
aplenty in the falling apart of molecules at surfaces, the
beautiful story I just told was pretty classical. Sometimes the
dynamics of chemical reactions have truly nonclassical features,
ones that derive from the quantum nature of molecules. For
molecules are truly betwixt and between—part classical objects,
sculpted in their multifarious richness as macroscopic
structures are, part quantum objects with the seemingly arcane
consequences of the quantum world.  A remarkable report recently
appeared from Richard Zare's Stanford University group that
exemplifies quantum mysteries, even as it has a partially
classical explanation. Diatomic molecules can be induced to fall
apart by either heat or light. The Stanford group looked at a
simple diatomic, ICl (the mixed partner to familiar diatomic
chlorine, Cl2, and iodine, I2) and its photodissoc