μSR in polyacetylenes

Nagamine, K.; Ishida, K.

doi:10.1007/bf02394952

Cited by 9 publications

(3 citation statements)

References 13 publications

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“…The intermittent hyperfine interaction between the electron and the muon in such a situation would be an efficient mechanism for spin relaxation. Longitudinal muon spin relaxation rates determined by LF-mSR have been used to probe electron conduction in several conducting polymers [48][49][50][51][52][53][54][55][56] and Drew et al…”

Section: Col H and I Phasesmentioning

confidence: 99%

Muon spin spectroscopy of the discotic liquid crystal HAT6

McKenzie

Cammidge

Dilger

et al. 2010

Phys. Chem. Chem. Phys.

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Avoided level crossing muon spin resonance (ALC-muSR) has been used to study the cyclohexadienyl-type radicals produced by the addition of muonium (Mu) to the discotic liquid crystal HAT6 (2,3,6,7,10,11-hexahexyloxytriphenylene) in the crystalline (Cr) phase, the hexagonal columnar mesophase (Col(h)) and isotropic (I) phase. In the Cr phase unpaired electron spin density can be transferred from the radical to neighboring HAT6 molecules depending on the overlap of their pi-systems and hence on the relative orientation of the triphenylene rings. The two Delta(1) resonances in the ALC-muSR spectra of the Cr phase indicate that the neighboring HAT6 molecules have two preferred orientations with respect to the radical: one which results in negligible spin density transfer and a second where 17% of the unpaired spin density is transferred. The ALC-muSR spectra in Col(h) and I phases are substantially different from those of the Cr phase in that there are two narrow resonances superimposed on an extremely broad and intense resonance. The narrow resonances are due to highly mobile radicals located in the aliphatic region between the columns and the broad resonance is due to radicals incorporated within the columns of HAT6 molecules. The large width and amplitude of this resonance indicates that the radicals within the columns are undergoing rapid electron spin relaxation but the mechanism that causes this relaxation is unknown.

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Section: Col H and I Phasesmentioning

confidence: 99%

Muon spin spectroscopy of the discotic liquid crystal HAT6

McKenzie

Cammidge

Dilger

et al. 2010

Phys. Chem. Chem. Phys.

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“…The first muon relaxation experiments on the conducting polymers were carried out by Nagamine and co-workers in the mid-1980s on the simplest conducting polymer, polyacetylene (PA) [6][7][8][9][10][11] (see figure 1). Implanted muons were used to probe the properties of mobile spin excitations in the trans isomer of PA.…”

Section: Polyacetylene and 1d Diffusion Modelsmentioning

confidence: 99%

Muon spin relaxation as a probe of electron motion in conducting polymers

Pratt¹

2004

J. Phys.: Condens. Matter

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The use of implanted muons to probe the dynamics of electronic excitations in conducting polymers is reviewed. Early work on polyacetylene showed evidence for mobile solitons performing one-dimensional diffusion in the trans isomer and localized spins in the cis isomer. Subsequent muon studies on a range of conducting polymers have shown evidence for mobile polaronic excitations and microscopic transport properties for these polarons have been derived from the measurements. A theoretical framework was developed by Risch and Kehr to describe the intermittent hyperfine coupling between a static muon and an electron diffusing randomly through a chain of sites. This theory predicts a specific form for both the muon spin relaxation function and the field dependence of the relaxation rate. The experimental data are found to be described well by this model. Intrachain diffusion rates can be extracted from the data; in several cases an interchain diffusion rate can also be measured. The anisotropy of diffusion rates can be as high as 104 at low temperatures, reducing typically to 102 or less at room temperature. The importance of molecular vibrational modes in controlling the electronic motion in the polymer has been shown.

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“…Satisfactory description of experimental data using (2) suggests that the mean time between electronic defect spin flips, λ, is short compared to the experimental timescale, t max . The relaxation function follows a t −1/2 form [13] at long times rather than showing an exponential decay as observed in early μSR studies of conducting polymers [14]. It should be mentioned that while Risch and Kehr considered spin relaxation in zero applied field, application of their model function to experimental zero-field data from trans-polyacetylene proved unsatisfactory.…”

Section: Modelling Muon Relaxation Spectramentioning

confidence: 86%

Electron transfer in dextran probed by longitudinal field muon spin relaxation

Telling

Kilcoyne

2006

J. Phys.: Condens. Matter

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Electron-transfer processes play a crucial role in bio-nanobattery design, the electron transfer rate through the organic material being a key parameter in determining the resistance, maximum current, power density, discharge rate and duty cycle of the cell. The labelled electron method using positive muons allows such transfer processes in macromolecules, such as polymers and proteins, to be probed on a microscopic level. Here we present the results of an experiment using the labelled electron method with longitudinal field muon spin relaxation (LF-μSR) to investigate electron-transfer processes in dextran. The data are well described using the Risch-Kehr model and the results suggest intra-chain diffusion is the dominant transport process in this system between 15 and 250 K. Intra-chain diffusion rates of 10 13 s −1 have been determined.

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μSR in polyacetylenes

Cited by 9 publications

References 13 publications

Muon spin spectroscopy of the discotic liquid crystal HAT6

Muon spin spectroscopy of the discotic liquid crystal HAT6

Muon spin relaxation as a probe of electron motion in conducting polymers

Electron transfer in dextran probed by longitudinal field muon spin relaxation

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