Fast-computational approach to the evaluation of slow-motion EPR spectra in terms of a generalized Langevin equation

Giordano, Marco; Grigolini, Paolo; Leporini, Dino; Marin, Paolo

doi:10.1103/physreva.28.2474

Cited by 60 publications

(26 citation statements)

References 19 publications

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“…We now illustrate how the ESR lineshape conveys information on the rotational dynamics of the spin probe (33)(34)(35). Additional details are found in SI Appendix.…”

Section: Outine Of Esr Spectroscopymentioning

confidence: 99%

ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water

Banerjee

Bhat

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Using electron spin resonance spectroscopy (ESR), we measure the rotational mobility of probe molecules highly diluted in deeply supercooled bulk water and negligibly constrained by the possible ice fraction. The mobility increases above the putative glass transition temperature of water, T g ‫؍‬ 136 K, and smoothly connects to the thermodynamically stable region by traversing the so called ''no man's land'' (the range 150 -235 K), where it is believed that the homogeneous nucleation of ice suppresses the liquid water. Two coexisting fractions of the probe molecules are evidenced. The 2 fractions exhibit different mobility and fragility; the slower one is thermally activated (low fragility) and is larger at low temperatures below a fragile-to-strong dynamic cross-over at Ϸ225 K. The reorientation of the probe molecules decouples from the viscosity below decoupling of transport properties ͉ dynamic cross-over in water ͉ dynamic heterogeneity ͉ supercooled water ͉ polycrystalline materials T he physical properties of water are far from being completely understood. Several thermodynamic and dynamic anomalies are known or anticipated in the metastable supercooled regime that influence the equilibrium states and have deep impact in biology, astrophysics, glaciology, and atmospheric science (1-3). At ambient pressure, the supercooled regime ranges between the commonly accepted value of the glass transition temperature T g ϭ 136 K and the freezing temperature T m ϭ 273.15 K. Above T g , amorphous water transforms into a highly viscous fluid (4, 5). Crystallization into metastable cubic ice (I c ) at T X Ϸ 150 K with further transformation to the usual hexagonal form of ice I h is reported (1, 6). On the other hand, bulk water at atmospheric pressure can be supercooled below its melting temperature down to the homogeneous nucleation temperature T H Ϸ 235 K, below which it usually crystallizes to I h . Thus, the region between T X and T H is often regarded as a region where liquid water cannot be observed [''no man's land,'' NML (1)]. Nonetheless, the coexistence of crystals and deeply supercooled liquids was suspected almost 1 century ago for bulk systems (7). More recently, evidence that water and cubic ice coexist in thin films in the temperature range 140-210 K was reported (8-11). The existence of liquid water has been also shown experimentally in veins (or so-called triple junctions) of polycrystalline ice (12) that serve as interfacial reservoirs for impurities (13-15). The size of such reservoirs is thermodynamically defined by surface forces and also by the curvature of the surface (i.e., the Kelvin effect in veins) (11, 16). In pure ice, the reservoir size increases when approaching the melting point (17). Notably, recent simulations concluded that in polycrystalline materials grain boundaries exhibit the dynamics of glass-forming liquids (45).This background motivated us to investigate the coexistence of ice and supercooled water in large volumes in an attempt to characterize the dynamical properties of the li...

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“…We now illustrate how the ESR lineshape conveys information on the rotational dynamics of the spin probe (33)(34)(35). Additional details are found in SI Appendix.…”

Section: Outine Of Esr Spectroscopymentioning

confidence: 99%

ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water

Banerjee

Bhat

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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“…**To whom correspondence should be sent. in the slow.motion region, when the rotational correlation time, r, characterizing the molecular dynamics is long on the ESR time scale, r ~ 2 × 10 -9 S. The problem has, however, largely been overcome in recent years with the development of fast numerical algorithms for the solution of the stochastic Liouville equation which provides the basic description of the ESR spectra [10][11][12]. It has thus become feasible to simulate the observed ESR spectra directly, without recourse to calibration curves or comparison with standard spectra.…”

Section: Introductionmentioning

confidence: 99%

Q-band electron spin resonance studies of slow motions in bilayers with high order

Koole¹,

Dammers²,

Levine³

1984

Chemistry and Physics of Lipids

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Q-band electron spin resonance (ESR) experiments on macroscopically oriented multilayers of dimyristoyl l~eithin/cholesterol (2:1 molar ratio)/cholestane spin label, order parameter S ,~ 1, have been carried out in the temperature range -32"C to +20"C. The spectra were simulated by a numerical soultion of the stochastic Liouville equation using Pad6 approximants. The simulations show that the rates of reorientation of the spin label molecules about their long axes fall within the slow-motion regime. At low temperatures the molecular motion is best described in terms of a small step diffusion model, while at the higher temperatures a random jump model or an intermediate jump model provides a better description.

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“…It should be noted that homogeneous broadening enters the simulations through an effective electron spin-spin relaxation time T2e [3][4][5][6].…”

Section: Methodsmentioning

confidence: 99%

“…However, the information about the orientational order and dynamics of the molecules cannot often be extracted in a straightforward manner from the observed ESR spectra [2,3]. This is particularly difficult in the slow-motion region, when the rotational correlation time, ~', characterizing the molecular dynamics is long on the ESR time scale, • >_, 2 • 10 -9 s. The problem has largely been overcome in recent years with the development of fast numerical algorithms for the solution of the stochastic Liouville equation which provides the basic description of the ESR spectra [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…We have used the slow-tumbling ESR formalism [3][4][5][6] to analyse X-band ESR spectra of CSL incorporated into planar multibilayers of diacyldigalactosyldiglyceride (DGDG)/water mixtures. DGDG is an important component of 298 thylakoid membranes of chloroplasts [7,8] and contains fatty acid chains with a high degree of unsaturation (about 70-80% 18:3 fatty acids).…”

Section: Introductionmentioning

confidence: 99%

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Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

Dammers

Ginkel

Levine

1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The orientation and restricted motion of the cholestane spin label (3-spiro-doxyl-5a-cholestane) incorporated into planar muitibilayers of diacyldigalactosyldiglycerides extracted from the thylakoid membranes of chloroplasts from different plant leaves has been studied. The experimental ESR spectra were simulated in terms of the slow-tumbling ESR formalism of Freed and co-workers (Polnaszek, C.F., Bruno, G.V. and Freed, J.H. (1973) J. Chem. Phys. 58, 3185-3199). The analysis shows that the degree of orientational order is low. The spin label molecules undergo a faster reorientational motion about their long molecular axes than perpendicular to them. At room temperature the reorientational rate around the long molecular axis falls within the fast-motionai limit, while the reorientation rate of the long axis itself corresponds to the slow-tumbling regime. The results indicate that the motion of the labels in bilayers of diacyldigalactosyldiglycerides is considerably slower than that of the same label incorporated into bilayers of saturated phosphatidylcholines above the main phase transition. Differences between bilayers of diacyldigalactosyldiglycerides extracted from different plant membranes have been observed.

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Fast-computational approach to the evaluation of slow-motion EPR spectra in terms of a generalized Langevin equation

Cited by 60 publications

References 19 publications

ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water

ESR evidence for 2 coexisting liquid phases in deeply supercooled bulk water

Q-band electron spin resonance studies of slow motions in bilayers with high order

Slow-motion ESR of cholestane spin labels in planar multibilayers of diacyldigalactosyldiglycerides

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