Electron-Spin Resonance of N4- Defects in Irradiated RbN3
Abstract
An N4- molecular ion is observed by ESR at 92 K in single-crystal rubidium azide (RbN3) following uv or γ irradiation at 77 K and a 35-min anneal at 227 K. The ESR spectra are characteristic of an unpaired electron interacting equally with four equivalent nitrogen nuclei. The spin-Hamiltonian parameters are similar to those of the planar N4- defect in KN3; however, the growth and annealing behaviors of this defect differ in these two crystals. For both materials, trapped nitrogen atoms found following irradiation anneal at about 150 K. In both, N4- ions are formed from thermal annealing at approximately 200 K; however, the N2- intermediate reported in KN3 is not identified in RbN3. Slow thermal decay of N4- defects in RbN3 occurs at temperatures as low as 227 K. From measurements of the rate of decay at several temperatures an annealing activation energy of 0.47+/-0.04 eV is determined, which is approximately one-half that found for N4- ions in KN3.
- Publication:
-
Physical Review B
- Pub Date:
- May 1973
- DOI:
- 10.1103/PhysRevB.7.4047
- Bibcode:
- 1973PhRvB...7.4047G