Spectral hole burning: Spontaneous and photoinduced tunneling reactions in low temperature solids

Abstract

Spectral hole burning is frequently observed in molecular solids when a solute dye molecule in a solvent matrix at very low temperature is irradiated with light having a narrow frequency bandwidth. This phenomenon relies on photo induced changes of the absorption spectrum of the solute. All photochemical reactions lead in principle to such changes, but the extreme sensitivity of the method makes it particularly suitable for the characterization of reactions that occur at cryogenic temperatures with very small yield and that would be difficult to observe by conventional methods. Here we will discuss in more detail the contribution of proton tunneling reactions to spectral hole burning and in particular new results obtained in pentacene doped benzoic acid crystals, which is an excellent model system. © 1995 IUPAC