Effect of glassy modes on spin-lattice relaxation of TEMPO radical in ethanol (CROSBI ID 588188)
Prilog sa skupa u zborniku | sažetak izlaganja sa skupa | međunarodna recenzija
Podaci o odgovornosti
Merunka, Dalibor ; Kveder, Marina ; Jokić, Milan ; Rakvin, Boris ;
engleski
Effect of glassy modes on spin-lattice relaxation of TEMPO radical in ethanol
Spin-lattice relaxation (SLR) of TEMPO radical in the glassy (G) and crystalline (C) ethanol was measured by X-band EPR technique between 5 and 80 K. The SLR rates Gamma=1/T1 are higher in G- ethanol than in C-ethanol for both protonated and deuterated samples, while the excess SLR rate in G-ethanol DGamma=Gamma(G)−Gamma(C) is much higher for the protonated sample (Fig. 1). The results indicate that DGamma is produced by extra modes existing in glassy matrix, which are coupled to the electron spin of radical by the electron- nuclear dipolar (END) interaction. Using the soft- potential model for glassy modes and assuming END interaction between the electron spin and matrix protons, the expressions for SLR rates due to various mechanisms of glassy modes was derived. The SLR rates were evaluated for protonated G- ethanol from reported experimental data. The results indicate two effective mechanisms: thermally activated relaxation of double-well systems (DWS) and phonon-induced relaxation of quasi-harmonic local modes (QLM). The SLR rate induced by these mechanisms correlates well with the experimental DGammain both the order of magnitude and the temperature dependence (Fig. 1).
electron spin-lattice relaxation; dynamics of glasses
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Podaci o prilogu
206-206.
2012.
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objavljeno
Podaci o matičnoj publikaciji
EUROMAR 2012 Magnetic Resonance Conference
Dublin:
Podaci o skupu
EUROMAR 2012
poster
01.07.2012-05.07.2012
Dublin, Irska