Abstract

Tunneling phenomena manifest itself essentially in two different ways. One is the displacement of particles across energy barriers without the need of thermal activation. This is a relaxation phenomenon and accounts for the occurrence of chemical reactions at 0 K and the evolution of glasses which continues at the lowest temperatures and leads to such observations as spectral diffusion. The other is the splitting of energy levels in a potential having several identical minima. This splitting lifts the degeneracy of states which describe the particle localized in one of the (isolated) wells. This tunneling splitting (also called tunneling matrix element) has its origin in the "transparency" of the energy barrier and measures the amplitude of the wavefunction in the classically forbidden regions of the potential.

© 1992 Optical Society of America