Resonance muon spin

Multistep catalytic cycles (continued) reductive elimination reactions, 1, 121 Muon spin resonance, metallocene-based magnets,... 

Muonium (Mu) is the lightest hydrogen-like atom (mMu = 0.11 mH) available for chemical research it has a positive muon (/jl+, t = 2.2 fisec) as the nucleus. The muon spin resonance (/tSR) technique is described in several review articles (16, 99—102). Most of the research is performed in the condensed phases, but because of the development of the surface muon beams (103, 104), experiments in the gaseous phase have received more attention. At present three muonic fractions can be detected (1) fan, free muonium (2) fa, free n+, or Mu bound in a diamagnetic compound and (3) fa, Mu bound in a paramagnetic compound. In liquid phases, there is quite often a missing fraction, fa = 1 -fau - fa - fa ... 

Muonium-substituted free radicals contain the muon as a polarized spin label which allows its detection either by the transverse field muon spin rotation (TF-pSR) technique or by longitudinal field avoided-level-crossing muon spin resonance (ALC-pSR) [4]. 

Muons are elementary particles that have the same charge as a proton and l/9th of its mass. When introduced in a chemical setting like an oxide, they thus behave like a light hydrogen ion isotope. They can take up an electron and become muonium, a hydrogen-like atomic species. They have short lifetimes, but one may study their oxidation state and environment by muon spin resonance (pSR) spectroscopy (an analog to NMR spectroscopy). This has been used to study hydrogen in semiconductors [34] and in some cases in relevant oxides [35]. 

The term pSR was originally used for muon spin rotation , but muon spin science has now developed into a variety of techniques and is not limited to the rotation technique. It is fortunate, however, that most of the other techniques (muon spin relaxation, muon spin repolarization, and muon spin resonance) have the same abbreviated form pSR. Thus pSR is sometimes used to describe all these techniques collectively. When it is necessary to specify these different techniques, pS Rotation , pS Resonance , etc. will be used. 

As in NMR, muon spin resonance occurs under a longitudinal magnetic field and RF. When the RF frequency becomes equal to (Hg is the applied magnetic field), the spin starts to evolve, and the time dependence of the on-resonance component follows the expression,... 

Avoided-level crossing muon spin resonance (ALC-p.SR), a derivative of the NMR technique, can be applied to systems in which adsoAed flee radicals are formed by loss of H [94Schl]. When bombarded with highly-polarized positive mirons (p., these radicals can combine with muonittm... 

The term Muon Spin Resonance defines a NMR-type technique. In the presence of a static external field one induces muon spin flips by the application of resonant radio frequency (Kitaoka et al. 1982, Kreitzman 1990, Hampele et al. 1990, Nishiyama 1992, Scheuermann et al. 1997, Cottrell et al. 1997) or microwave field (Kreitzman et al. 1994). The resonance condition is detected via a loss of muon polarization. As in NMR, firequency shifts and linewidth are the sensitive parameters. 

High-temperature data up to 1200K have been reported in connection with studies on iron above the Curie temperature (Herlach et al. 1986). These types of experiments include muon spin resonance data (Hampele et al. 1990) with a surface beam. The main... 

Recently, the observation of the muon spin resonance signal has been reported (Lord 1998) for YFe2 at room temperature (i.e., in the FM regime). The weak, but distinct resonance is seen at 30.6 MHz in ZF with an RF-field of 0.8 mT. This value agrees perfectly with the result of Barth et al. (1986a). This was just a basic test of feasibility and no further discussion is given. 

ESR is muon spin resonance (pSR), carried out at high-energy accelerator sources such as TRIUME (Vancouver, Canada) that provide muons. 

Example of application Fluorescence spectroscopy, synchrotron radiation Rutherford back-scattering on surfaces Positron annihilation spectroscopy Muon spin resonance spectroscopy Radiation detectors, radiochemistiy Mossbauer effect Nuclide production, activation analysis... 

Positron annihilation spectroscopy (PAS) is used in research on free volume (95) or on aging effects in polymers (96), and muon spin resonance with muon beams (97) 5delds information on d5mamic processes in polymers (98), but specimen size may be limited. 

ALC- J,SR avoided-level-crossing muon spin resonance ( jLCR)... 

RKKY Ruderman-Kittel-Kasuya-Yosida (xSR muon spin resonance... 

Muon Spin Resonance Spectroscopy, Applications Ivan D Reid and Emil Roduner Pages 1439-1450... 

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