Merunka, Dalibor; Kveder, Marina; Jokić, Milan; Rakvin, Boris (2013) Effect of glassy modes on electron spin-lattice relaxation in solid ethanol. Journal of Magnetic Resonance, 228 . pp. 50-58. ISSN 1090-7807
Abstract
Electron spin-lattice relaxation (SLR) of TEMPO radical was measured in the crystalline and glassy states of deuterated ethanol in the temperature range 5-80 K using X-band electron paramagnetic resonance (EPR). The measured SLR rates are higher in the glassy than in crystalline state and the excess SLR rate in glassy state is much lower than in ethanol. This result suggests that extra modes in glassy state, i.e. glassy modes, produce the excess SLR rate via the electron-nuclear dipolar (END) interaction between the electron spin of radical and the matrix protons or deuterons. Using the soft-potential model and assuming the END interaction between the electron spin and the matrix protons, the contributions to SLR rate of various mechanisms of glassy modes were theoretically analyzed. The evaluations of SLR rates in glassy ethanol indicate two main mechanisms of glassy modes: thermally activated relaxation of double-well systems and phonon-induced relaxation of quasi-harmonic local modes. The SLR rates induced by these mechanisms correlate well with the experimental data.
| Item Type: | Article | ||||||||||||
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| Uncontrolled Keywords: | glassy state; electron spin-lattice relaxation; glassy modes; soft-potential model | ||||||||||||
| Subjects: | NATURAL SCIENCES > Physics NATURAL SCIENCES > Physics > Condensed Matter Physics |
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| Divisions: | Division of Physical Chemistry | ||||||||||||
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| Depositing User: | Marina Ilakovac Kveder | ||||||||||||
| Date Deposited: | 17 Apr 2019 10:49 | ||||||||||||
| URI: | http://fulir.irb.hr/id/eprint/4494 | ||||||||||||
| DOI: | 10.1016/j.jmr.2012.12.016 |
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