Dynamics and local environment of an aromatic counterion bound to di-chain cationic surfactant bilayers studied by avoided level crossing muon spin resonance: evidence for counterion condensation

Avoided level crossing muon spin resonance (ALC-μSR) was used to study the dynamics of muon-spin-labelled 2,4,6-trimethylbenzoate counterions and their interaction with DODMAC (dioctadecyldimethylammonium chloride) bilayers in the Lα and Lβ states.

Magnetic Resonance Spectroscopy

Since the original observation by Zeeman, that spectral lines can be affected by magnetic fields, ‘magnetic spectroscopy’ has evolved into the broad arsenal of techniques known as ‘magnetic resonance’. This review focuses on nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and muon spin resonance (μSR): methods which have provided unparalleled insight into the structures, reactivity and dynamics of molecules, and thereby contributed to a detailed understanding of important aspects of chemistry, and the materials, biomedical, and environmental sciences. Magnetic resonance imaging (MRI), in vivo magnetic resonance spectroscopy (MRS) and functional magnetic resonance spectroscopy (fMRS) are also described. EPR is outlined as a principal method for investigating free radicals, along with biomedical applications, and mention is given to the more recent innovation of pulsed EPR techniques. In the final section of the article, the various methods known as μSR are collected under the heading ‘muon spin resonance’, in order to emphasise their complementarity with the more familiar NMR and EPR.

Spin clusters and low-energy excitations in rare earth kagome systems

The rare earth kagome systems R3Ga5SiO[Formula: see text] (R = Nd or Pr), which are weakly frustrated antiferromagnets, do not exhibit long-range order at temperatures down to 40 mK as revealed by neutron scattering. The neutron experiments provide evidence for the emergence at low temperatures of correlated spins in nanoscale cluster regions with magnetic field-dependent correlation lengths. A variety of techniques have been used to determine the magnetic and thermal properties of these systems. In particular, high-field electron spin resonance (ESR), nuclear magnetic resonance (NMR) and muon spin resonance ([Formula: see text]SR) experiments have established that dynamic correlation of spins remains significant at temperatures well above 1 K. ESR provides evidence for spin wave excitations in spin clusters and the spectra have been interpreted using a Heisenberg model approach. While Nd[Formula: see text] (J = 9/2) is a Kramers ion Pr[Formula: see text] (J = 4) is not. This difference leads to contrasts in the magnetic properties of the two systems. This review surveys the information that has been obtained on the properties of these kagome materials over the past decade.

Partitioning of 2-phenylethanol and limonene cosurfactants in C12E4

Avoided level-crossing muon spin resonance (ALC-μSR) has been used to study the dynamics and local environment of spin probes formed by muonium (Mu) addition to 2-phenylethanol (PEA) and limonene (1-methyl-4-(1-methylethenyl)-cyclohexene) in an aqueous dispersion of the nonionic surfactant C12E4 (tetra(ethylene glycol) n-dodecyl ether).