Low-temperature electron-spin relaxation in the crystalline and glassy states of solid ethanol

X-band electron paramagnetic resonance spectroscopy was used to study the spectral properties of a nitroxide spin probe in ethanol glass and crystalline ethanol, at 5 – 11.5 K. The different anisotropy of molecular packing in the two host matrices was evidenced by different rigid limit values for maximal hyperfine splitting in the signal of the spin probe. The significantly shorter phase memory time Tm for the spin probe dissolved in crystalline ethanol, as compared to ethanol glass, was discussed in terms of contribution from spectral diffusion. The effect of low-frequency dynamics was manifested in the temperature dependence of Tm and in the difference between the data measured at different spectral positions. This phenomenon was addressed within the framework of the slow-motional isotropic diffusion model S. Lee and S. Z. Tang, Phys. Rev. B 31, 1308 1985 predicting the spin probe dynamics within the millisecond range, at very low temperatures. The shorter spin-lattice relaxation time of the spin probe in ethanol glass was interpreted in terms of enhanced energy exchange between the spin system and the lattice in the glass matrix due to boson peak excitations.

[1]  F. Bermejo,et al.  Comment on "crystal-like nature of acoustic excitations in glassy ethanol". , 2007, Physical review letters.

[2]  V. Rodriguez-Mora,et al.  Calorimetric and acoustic experiments on orientationally disordered and fully ordered crystalline phases of ethanol , 2007 .

[3]  E. Duval,et al.  Boson peak and hybridization of acoustic modes with vibrations of nanometric heterogeneities in glasses , 2007 .

[4]  M. Capitán,et al.  On the phase diagram of polymorphic ethanol: Thermodynamic and structural studies , 2006 .

[5]  A. Krivchikov,et al.  Scattering of acoustic phonons in disordered matter : A quantitative evaluation of the effects of positional versus orientational disorder , 2006 .

[6]  A. Ilakovac,et al.  Direct evidence for the glass-crystalline transformation in solid ethanol by means of a nitroxide spin probe , 2006 .

[7]  J. C. Phillips,et al.  Slow dynamics in glasses : A comparison between theory and experiment , 2005, cond-mat/0505455.

[8]  A. Sharma,et al.  Vitrification and glass transition of water: insights from spin probe ESR. , 2004, Physical review letters.

[9]  I. A. Grigoriev,et al.  Orientational motion of nitroxides in molecular glasses: dependence on the chemical structure, on the molecular size of the probe, and on the type of the matrix. , 2004, The Journal of chemical physics.

[10]  F. Bermejo,et al.  Critical dynamics near the glass transition as explored with muon spin relaxation , 2004 .

[11]  S. Santucci,et al.  Crystal-like nature of acoustic excitations in glassy ethanol. , 2004, Physical review letters.

[12]  N. Dalal,et al.  Heat capacity and electron spin echo evidence for low frequency vibrational modes and lattice disorder in L-alanine at cryogenic temperatures. , 2004, The Journal of chemical physics.

[13]  F. Bermejo,et al.  Slow dynamics about the glass transition as explored by muon spin relaxation spectroscopy , 2003 .

[14]  D. Parshin,et al.  Anharmonicity, vibrational instability, and the Boson peak in glasses , 2002, cond-mat/0203165.

[15]  C. Talón,et al.  Low-temperature specific heat of amorphous, orientational glass, and crystal phases of ethanol , 2002 .

[16]  C. Talón,et al.  The Boson peak in structural and orientational glasses of simple alcohols: specific heat at low temperatures , 2002, cond-mat/0201560.

[17]  M. Augustyniak-Jabłokow,et al.  Dephasing relaxation of the electron spin echo of the vibronic Cu(H(2)O)(6) complexes in Tutton salt crystals at low temperatures. , 2001, Journal of magnetic resonance.

[18]  Gunnar Jeschke,et al.  Principles of pulse electron paramagnetic resonance , 2001 .

[19]  M. Brustolon,et al.  Dynamics and spin relaxation of tempone in a host crystal. An ENDOR, high field EPR and electron spin echo study , 1999 .

[20]  S. Misra.  Spin-lattice relaxation times in amorphous materials as effected by exchange interactions, tunneling level states (TLS) centres, and fractons , 1998 .

[21]  C. Talón,et al.  Low-temperature specific heat and glassy dynamics of a polymorphic molecular solid , 1998 .

[22]  D. Price,et al.  Quantitative Assessment of the Effects of Orientational and Positional Disorder on Glassy Dynamics , 1997 .

[23]  U. Wiesner,et al.  Characterization of the motion of spin probes and spin labels in amorphous polymers with two-dimensional field-step ELDOR , 1996 .

[24]  Cannistraro,et al.  Continuous-wave and pulsed-EPR study of the 65Cu2+-doped NaOD-water system in the amorphous and polycrystalline phases. , 1993, Physical review. B, Condensed matter.

[25]  Fayer,et al.  Time scales and optical dephasing measurements: Investigation of dynamics in complex systems. , 1989, Physical review. B, Condensed matter.

[26]  Sook Lee,et al.  Comparison of different theories for slow‐tumbling axial nitroxide ESR hyperfine centers in polycrystalline‐amorphous substances , 1985 .

[27]  Lee,et al.  General behavior of completely anisotropic ESR hyperfine centers under slow orientational diffusion motion. , 1985, Physical review. B, Condensed matter.

[28]  Sook Lee,et al.  Generalized theoretical treatment of axially symmetric ESR hyperfine centers under slow orientational diffusion motion , 1984 .

[29]  A. Baram.  Slow motion lineshapes , 1981 .

[30]  G. Soda,et al.  Molecular motions in polymorphic forms of ethanol as studied by nuclear magnetic resonance , 1980 .

[31]  J. Freed,et al.  ESR studies of anisotropic rotational reorientation and slow tumbling in liquid and frozen media. II. Saturation and nonsecular effects , 1973 .

[32]  J. Freed,et al.  An ESR Study of Anisotropic Rotational Reorientation and Slow Tumbling in Liquid and Frozen Media , 1972 .

[33]  J. Freed,et al.  Electron spin resonance line shapes and saturation in the slow motional region , 1971 .

[34]  Philip W. Anderson,et al.  Spectral Diffusion Decay in Spin Resonance Experiments , 1962 .