Strange States of Molecules

The superposition principle of quantum mechanics immediately gives rise to what have been termed strange states. These can be illustrated by reference to the ammonia molecule. 

Let us consider Fig. 3 in which a double-minimum function represents the Born-Oppenheimer potential for the electronic ground-state of ammonia. This is an energy versus internal inversion coordination diagram. Every value of the inversion coordinate corresponds to a particular nuclear framework for ammonia. The two minima, for example, correspond to pyramidal structures, whereas the maximum corresponds to a planar 

FIGURE 3 Illustration of the superposition principle using ammonia and ammonia-type molecules. 

FIGURE 4 Sketched distribution of the nuclei in the ground state of an ammonia-type molecule. 

The transition between the two stationary states and is the ammonia-maser transition with transition frequency v = (E — E )/h = 23,870,110,000 s . The very existence of the ammonia-maser transition suggests that the states I. and I, of ammonia do indeed exist in reality and not just in the quantum-mechanical formalism. 

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