On the Nature of Electron Traps in Hydrocarbon Glasses at Low Temperatures

Abstract

AbstractA delicate application of the EPR linewidth theory to the experimentally measured trapped electron (e−ϵ) linewidths in three kinds of isotopic 3‐methyl‐pentane molecules (3MP) concludes that the electron traps are formed by the protons regardless of their relative positions in the molecule. With the cavity radius of <2 Å, the trapped electron charge density in these nonpolar hydrocarbon glasses is shown to be highly delocalized. The slower thermal decay rate of e−ϵ 3MPd14 than in 3MPh14 is most likely related to the deeper trap depth in the former than in the latter leading to a predicted blue shift absorption peak for e−ϵ in 3MPd14 relative to that in 3MPh14 The farther travel distance for mobile electrons before being trapped in these matrices than in polar matrices is attributed to the low trapping cross section rather than a low trap density. Consistency of the empirical cavity radius with the predicted value from current theoretical basis is also cited.