Frozen-in disorder probed by electron spin relaxation

• Published in: Solid state communications Vol. 167; pp. 23 - 26
• Main Authors: Kveder, M., Rakvin, B., Jokić, M., Reijerse, E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2013; Elsevier
• Subjects: A. Ethanol; B. Glassy state; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Spectral diffusion in glass; E. EPR; Electron paramagnetic resonance and relaxation; Exact sciences and technology; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Physics; D. Spectral diffusion in glass; E. EPR; A. Ethanol; B. Glassy state; Paramagnetic center; Ethanol; Crystals; Glass; Relaxation time; Spatial distribution; Spin relaxation; Spin diffusion; Temperature effects; Electron paramagnetic resonance
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2013.04.034

Here we demonstrate that two extreme cases of molecular packing, i.e. the crystalline and glassy state of solid ethanol, which define the complete experimental span of attainable host matrix frustration, can be efficiently probed by measuring the electron spin phase memory relaxation time, TM, of an incorporated TEMPO nitroxyl radical at X-band EPR frequency. The sensitivity of TM is based on the spectral and spin diffusion effects which reflect the spatial distribution of involved spins as a function of molecular frozen-in disorder. By keeping the excited region of the EPR spectrum fixed one can monitor the changes in the density of spin packets, upon the state transformation of the host. EPR experiments performed at 94GHz show a clear difference in local distribution of paramagnetic centers in ethanol glass as compared to crystalline ethanol. The results support the idea that, by measuring TM and properties of density of spin packets, one can explore the extent of molecular disorder. •We investigate frozen-in disorder in solid ethanol by low-temperature EPR.•Spectral and spin diffusion are used to identify solid ethanol spatial frustration.•High-field EPR data show different host frustration in glassy/crystalline ethanol.