Electron-Spin Resonance of UV-Irradiated Sodium Azide.

摘要

Electron-spin-resonance (ESR) spectra were measured on NaN3 single crystals, uv irradiated at 77 K, and correlated with the optical-absorption spectra described in the preceding paper. A new ESR spectrum is observed, corresponding to spin S=1 in three inequivalent sites. The growth and decay of the spin-1 spectrum correlate, respectively, with the fast and slow annealing stages of the 565-nm optical absorption band, which occur below and above 220 K. The 565-nm band is attributed to spin-1/2 defects which form antiferromagnetically exchange-coupled pairs, and several models for these defects are considered. The 19-line F-center ESR spectrum correlates only with the less-stable component of the 735-nm band. The prominent single ESR line which remains after annealing of the 19-line spectrum is not correlated with the 610-nm band, contrary to previous reports. (Author)