Different structure types of vanadyl(V) orthophosphate [i.e. (VV ≡O)3+ orthophosphate] have been subjects of research due to their catalytic activity in the oxidation of n-butane to maleic anhydride. Electron paramagnetic resonance (EPR) spectroscopy can be exploited to elucidate the electronic structure of such compounds. When tuning the oxidation state of vanadium in (V1-xWx)OPO4, X-band EPR spectra

This review is inspired by the contributions from the University of Denver group to low-field EPR, in honor of Professor Gareth Eaton’s 80th birthday. The goal is to capture the spirit of innovation behind the body of work, especially as it pertains to development of new EPR techniques. The spirit of the DU EPR laboratory is one that never sought to limit what an EPR experiment could be, or how it

We review electric dipole active magnetic resonance and nonreciprocal directional dichroism in magnetoelectric multiferroic materials in terahertz and millimeter wave regions. Owing to dynamical magnetoelectric coupling generated by the spin-dependent electric polarization, magnetic resonance, which usually occurs owing to magnetic dipole transition, can be induced by the oscillating electric fields

Random fluctuations in the \(\tilde{g}\) and \(\tilde{A}\) matrices of a spin system due to thermal motion of a molecule are specifically considered to calculate the relaxation matrix for the four-level electron-nuclear spin-coupled system (\(S = 1/2\); \(I = 1/2\)) in a malonic acid crystal, using the formalism outlined by Lee et al. (J Chem Phys 98:3665–3689, 1993). The correlation time, τc, and

Experiments on proton and sodium MRI at 0.5 T are described to assess the sensitivity of various types of coils, namely solenoidal, surface, volumetric, and with specific complex geometry. Each type of coil, characterized by its geometric specificity, was built to record MR signal of protons (1H) and sodium (23Na) at 21.1 MHz and 5.6 MHz, respectively. Sodium coils were initially built for 1H MRI and

The lattice constants of Cs2MnBr4·2H2O crystals grown by the slow evaporation method were determined by X-ray diffraction. The thermal stability of Cs2MnBr4·2H2O was investigated as a function of its H2O content, and an endothermic peak at 378 K (= Tp) obtained by differential scanning calorimetry (DSC) was related to the loss of 2H2O. Thermogravimetric analysis (TGA) and DSC results revealed that

This letter aims to contribute to the debate around the difficulties and pitfalls with the interpretation of solid-state 13C nuclear magnetic resonance (NMR) spectra in graphitic materials, with special emphasis on the case of 13C-enriched samples and particularly dealing with the models used to fit the spectra recorded in magic angle spinning (MAS) experiments and the interpretation of the spectral

KCuCl\(_3\) is known to show a quantum phase transition from the disordered to antiferromagnetically ordered phases by applying pressure. There is a longitudinal excitation mode (Higgs amplitude mode) in the vicinity of the quantum critical point in the ordered phase. To detect the Higgs amplitude mode, high-pressure ESR measurements are performed in KCuCl\(_3\). The experimental data are analyzed

Electromagnetic simulation is a credible way to estimate the local specific absorption rate (SAR), which is a key consideration in high-field magnetic resonance imaging of the knee joint. To construct a subject-specific knee model, which is critical for SAR simulation, we proposed an architecture comprising multiple convolutional neural networks. Knee tissues were segmented by three U-Nets. Each network

In solid-state physics, pressure is an essential parameter, which can continuously change the interaction between electrons. The combination of terahertz electron spin resonance (THz ESR) with pressure is a powerful approach to clarify the spin state under pressure from the microscopic point of view, especially for quantum magnets. The most important feature of our high-pressure THz ESR system is that

We provide a perspective on how single-molecule magnets can offer a platform to combine quantum transport and paramagnetic spectroscopy, so as to deliver time-resolved electron paramagnetic resonance at the single-molecule level. To this aim, we first review the main principles and recent developments of molecular spintronics, together with the possibilities and limitations offered by current approaches

Manganese(I) based molecular squares of type [Mn(CO)3Br(μ-L)]4 where L = pyrazine, 4,4′-bipyridine, trans-1,2-bis(4-pyridyl)ethylene were synthesized and studied in detail by EPR spectroscopy. The continuous wave electron paramagnetic resonance (CW EPR) spectrum of these compounds consists of a broad transition at g = 2.006 and 4.16 that corresponds to an interacting low spin Mn(II) center and a narrow

The direct electron paramagnetic resonance (EPR) absorption between the singlet ground state and the triplet excited states of spin gap systems is investigated. Such an absorption, which is forbidden by the conservation of the total spin quantum number in isotropic Hamiltonians, is allowed by some anisotropies; the staggered g-tensor and the Dzyaloshinskii–Moriya interaction. Selection rules in the

We review terahertz (THz) electron spin resonance studies of two types of exotic quantum spin systems, namely, the spin(S)-1/2 one-dimensional (1D) Ising-like antiferromagnet BaCo\(_2\)V\(_2\)O\(_8\) and the S=1/2 two-dimensional (2D) honeycomb-like antiferromagnet Ba\(_3\)CuSb\(_2\)O\(_9\) in magnetic fields of up to 50 T. For the former subject, unconventional magnetic excitations were identified

This study investigates changes in the MRI contrast properties of Gd(III)-containing paramagnetic liposomes following the incorporation of photosensitizing agent (ZnPc—zinc phthalocyanine). It provides identification of mechanisms responsible for enhancement of proton relaxation rate and hence, the increased both r1 and r2 relaxivities. Five liposomal formulations, containing fatty acids derivatives

Compound I has been postulated to be the reactive species in many heme catalysts, which performs different chemistry and shows different properties in different enzymes. The aim of this review is to present a comprehensive model which has been successfully used to interpret the EPR spectra of various Compound I species. The theoretical approach established by seminal articles will be revisited and

Quantum spin systems are representative of strongly interacting quantum many-body systems. ESR theories for these systems require careful treatment of microscopic interactions between electron spins. In this article, we review several ESR theories in low-dimensional quantum spin systems by giving our particular attention to the detection of hidden magnetic modes that are found or would be found thanks

Bacteria overexpress, under condition of starvation or oxidative stress, Dps (DNA-binding proteins from starved cells), hollow sphere formed by 12 identical subunits endowed with ferritin-like activity. The iron oxidation and incorporation in Dps take place using H2O2 produced under starvation as preferred iron oxidant, thereby protecting bacteria from oxidative damage. Even if the role of Dps is well

The paper presents the electron paramagnetic resonance study of defects in the spin chain \(\hbox {o}-(\hbox {DMTTF})_2\hbox {X}\)family using continuous wave and pulsed techniques. The defects in spin chains are strongly correlated and present similar microscopic structure as a molecular magnet. By means of 2D-HYSCORE and DFT calculations, we show a strong reduction of hyperfine coupling between the

This study aimed to develop a refined actuator suitable for psoas major muscle (PM) MR elastography (MRE) and evaluate its measurement precision. MRE was performed on nine healthy volunteers. Discomfort under PM-MRE examinations was evaluated by discomfort scores using a four-point subjective scale. The performance of refined actuator was evaluated in detail; repeatability was evaluated using repeatability

Oligomers of poly(thiophene) and poly(ortho-phenyleneethynylene) having pendant S = 1/2 semiquinone radicals (as complexes of cobalt(III)) have been prepared and characterized by electron paramagnetic resonance (EPR) spectroscopy and magnetic measurements (superconducting quantum interferences device = SQUID magnetometry). Our results show that exchange coupling of semiquinone groups along a polythiophene

A series of heterometallic [TiIV7MIII] rings are reported which contain a single paramagnetic metal centre, either FeIII or CrIII. The structures contain an octagon of metals bridged by oxides within the ring and pivalate ligands outside the ring. The structures encapsulate a single cation, either a secondary ammonium cation or a cesium. Multi-frequency EPR spectroscopy was used to measure the zero-field

Proton Hyperfine Sublevel Correlation (1H-HYSCORE) experiments have been used to probe the ligation structure of the Fe(II) active site of taurine:2-oxoglutarate dioxygenase (TauD), a non-heme Fe(II) hydroxylase. To facilitate Electron Paramagnetic Resonance (EPR) experiments, Fe(II) derivatives of the enzyme were studied using nitric oxide as a substitute for molecular oxygen. The addition of NO to

We review past and recent work carried out on viscous liquids, amorphous and semicrystalline polymers by multifrequency high-field electron paramagnetic resonance (HF-EPR) facility in Pisa. The emphasis is on the enhanced ability to provide fine details of the reorientation process of the paramagnetic guest, the spin probe, revealing features driving the dynamics of the host system, including the energy-barrier

Graphene-derived materials attract a great deal of attention because of the peculiar properties that make them suitable for a wide range of applications. Among such materials, nano-sized systems show very interesting behaviour and high reactivity. Often such materials have unpaired electrons that make them suitable for electron paramagnetic resonance (EPR) spectroscopy. In this work we study by continuous

Phased-array coils are extensively employed in Magnetic Resonance (MR) as transmitter and receiver radiofrequency (RF) coils due to their large field-of-view (FOV) and their high signal-to-noise ratio (SNR). Array elements have to be geometrically decoupled for mutual coupling minimization, to achieve coil performance maximization. This paper proposes an analytical method for the mutual inductance

The flashback of the investigation of CuGeO3 doped with magnetic impurities carried out by high-frequency EPR brings to light physics still actual for one-dimensional S = 1/2 quantum spin chains and covering a vast area from disorder-driven quantum critical phenomena to a new type of magnetic oscillations. It is shown that a key opening the door for a better understanding of this field of research

A natural single crystal of amethyst was investigated by means of continuous-wave and pulsed Electron Paramagnetic Resonance (EPR), with the aim of structurally characterizing the substitutional S2 Fe(III):H+ centre. In this centre, Fe(III) replaces Si(IV) in the tetrahedral site, whereas H+ is coupled to Fe(III) to maintain the charge balance. The spectroscopic investigations, mainly the interpretation

The present work provides theoretical and experimental foundations for the ability of dinitrosyl iron complexes (DNICs) with thiol-containing ligands to be not only the donors of neutral NO molecules, but also the donors of nitrosonium cations (NO+) in living organisms ensuring S-nitrosation of various proteins and low-molecular-weight compounds. It is proposed that the emergence of those cations in

In this review, mechanically detected electron spin resonance (MDESR) in the terahertz (THz) region is described to demonstrate its usability as a novel methodology for obtaining microscopic insights into local electronic structures. Using micromechanical devices, the sensitivity to a small-volume sample is greatly enhanced even for a cavityless setup. Moreover, there are plenty of options in the setup

Spin traps, like 5,5-dimethyl-1-pyrroline N-oxide (DMPO), are commonly used to identify radicals formed in numerous chemical and biological systems, many of which contain metal-ion complexes. In this study, continuous wave electron paramagnetic resonance and hyperfine spectroscopy are used to prove the equatorial ligation of DMPO(-derived) molecules to Cu(II), even in the presence of competing nitrogen

To date, numerous studies have investigated the brain white matter abnormality in patients with alcohol dependence using diffusion tensor imaging (DTI). DTI has been primarily utilized to evaluate white matter integrity, it is now increasingly used to investigate microstructural changes of gray matter (GM), particularly the subcortical GM. We predicted that structural alterations may not only be restricted

Yakov Sergeevich Lebedev was a pioneer in high-frequency EPR, taking advantage of the separation of g-factor anisotropy effects from nuclear hyperfine splitting and the higher-frequency molecular motion sensitivity from higher-frequency measurements (Appl Magn Reson 7: 339–362, 1994). This article celebrates a second EPR subfield in which Prof. Lebedev pioneered, EPR imaging (Chem Phys Lett 99: 301–304

We shall introduce Kemeny–Snell distance (KSD) metric on metabolomics and validate results with partial least squares discriminant analysis (PLS-DA). KSD metric allows principally to identify the most relevant chemical shift ranges directly from spectra without metabolite library-limited signature search and quantitation. The one-dimensional proton nuclear magnetic resonance spectra of the serum of

High surface area TiO2 was synthetized by means of a solvothermal method and it was then used to prepare two photocatalysts based on copper-modified TiO2. Two different preparation approaches have been adopted based on the use of the same amount of Cu2O (0.5% w/w) as a reactant. The spectroscopic characterization shows that the two preparation procedures lead to distinct distributions of Cu2O and other

Polymer flooding is a vital method for the enhanced oil recovery of heterogeneous formations after water flooding. However, few visualization approaches are available to conduct the online monitoring and the non-invasive evaluation of polymer flooding experiments in natural rock cores. In this study, online dynamic magnetic resonance imaging (MRI) and T2 distribution measurements were employed to monitor

We present a 1H NMR investigation of spin dynamics in two finite integer spin molecular nanomagnetic rings, namely V7Zn and V7Ni. This study could be put in correlation with the problem of Haldane gap in infinite integer spin chains. While V7Zn is an approximation of a homometallic broken chain due to the presence of s = 0 Zn2+ ion uncoupled from nearest neighbor V2+ s = 1 ions, the V7Ni compound constitutes

This study compares the performance of two coil configurations for W-band pulsed ENDOR using a setup with both a radiofrequency ‘hairpin’ coil internal to a microwave non-radiative resonator and Helmholtz-like coils external to the resonator. Evaluation of the different coil performances is achieved via the ENDOR study of two model systems. The efficiencies of the coil configurations are first investigated

High-Frequency and -Field EPR (HFEPR) studies of Fe(TPP)X (X = F, Cl, Br; I, TPP2−= meso-tetraphenylporphyrinate dianion) and far-IR magnetic spectroscopic (FIRMS) studies of Fe(TPP)Br and Fe(TPP)I have been conducted to probe magnetic intra- and inter-Kramers doublet transitions in these S = 5/2 metalloporphyrin complexes, yielding zero-field splitting (ZFS) and g parameters for the complexes: Fe(TPP)F

The article presents a comparative review of experimental methods used for characterization of orientational ordering of the molecules in a partially aligned media. The optical, X-ray and magnetic resonance techniques are considered. The potential and limitations of different approaches are discussed. The magnetic resonance is concluded to be the most informative technique for detailed characterization

After the discovery of EPR by E.K. Zavoiski 1944 in Kazan (E.K. Zavoiski Zhurn Eksperimentalnoi i teoreticheskoi fiziki 15:344, 1945; E.K. Zavoiski J Phys USSR 9:211–245, 1945) EPR spectrometers were home-built and mostly dedicated to a special application. But commercial instruments in the contrary must be universal and cover a broad range of methods and applications. Therefore they should be compatible

This article discusses two different coherent quantum phenomena of magnonic bosons: Bose–Einstein condensation (mBEC) and Superfluid State of Magnons (SSM). What is the difference between the two? Magnon BEC is a quantum phenomenon determined by local density of bosonic quasiparticles. The superfluid state of magnons is a long-range coherent quantum state characterized by the rigidity of the order

Nuclear Magnetic Resonance relaxivities are a measure for the sensitivity of a contrast agent (CA), i.e. the potential of a paramagnetic moiety to enhance longitudinal and transverse relaxation of molecules in its near neighbourhood. The underlying mechanism is called Paramagnetic Relaxation Enhancement (PRE). The relaxivity, characterizing PRE, depends not only on the external applied magnetic field

Cerium hexaboride attracts attention of solid-state community for almost 50 years. Nowadays, this material is considered as a unique example of a system with orbital ordering resulting in formation of low-temperature magnetic phase with quadrupolar order, the so-called antiferroquadrupole phase. In crystal electric field 4f 1 state of Ce3+ splits into Γ7 doublet and Γ8 quartet, the latter is believed

A recent paper on solid-state 13C nuclear magnetic resonance in graphitic materials reports on the difficulties with the interpretation of the spectra and presents alternative methods to obtain informative experimental data. Therein, special emphasis is placed on the role of dipole–dipole interactions in the case of 13C-enriched samples and on the assignment of the 13C spectral components beyond the

The spin–spin interactions in the [Al2Er2 (µ3-OH)2(L)2(O2CPh-Me-p)6]·2MeCN compound are studied by electron paramagnetic resonance (EPR) on polycrystalline samples in different frequency ranges. The features of the shape of the EPR spectra of the compound built up of Al2Er2 clusters are analyzed and the EPR spectra are simulated with a spin Hamiltonian that also takes into account the dipole–dipole

Nuclear Magnetic Resonance (NMR) has been shown to be a useful technique to study the form and content of water in polymer composites. Composites using activated carbon fibres with phenolic resin have complex water absorption behaviour which would benefit from such investigation; however, the presence of the conductive fibres can make NMR problematic. In this study, single-sided NMR has been successfully

Copper(II)-, Fe(III)-, Zn(II)-, and Mn(II)-3,5-di-iso-propylsalicylate (3,5-DIPS) chelates and Cu(II)2(acetyl-3,5-DIPS)4, and 3,5-DIPS, salicylidene Schiff base chelates Mn(III), Co(II), Ni(II), were kinetically examined as antioxidants in the scavenging of tert-butyl peroxyl radical (\(tert - {\text{butylOO}}^{ \bullet }\)) in non-polar and polar aprotic solvents. Using kinetic EPR method absolute

EPR spectroscopy is an important spectroscopic method for identification and characterization of radical species involved in many biological reactions. The tyrosyl radical is one of the most studied amino acid radical intermediates in biology. Often in conjunction with histidine residues, it is involved in many fundamental biological electron and proton transfer processes, such as in the water oxidation

Monoisotopic \(^{53}\hbox {Cr}^{3+}\) impurity ions in scandium orthosilicate single crystal (\(\hbox {Sc}_2\hbox {SiO}_5\)) are studied by the method of electron paramagnetic resonance in the X-band frequencies. The directions of the main principal magnetic axes and the parameters of the effective spin Hamiltonian that describe the magnetic characteristics of the impurity centers of chromium, which

A strategy to combine two non-contrast-enhanced magnetic resonance angiography techniques is presented. It is based on arterial spin-labeled magnetic resonance imaging to visualize the arterial system at different time points to obtain information about hemodynamic properties in conjunction with a high-resolution time-of-flight angiography acquisition. The temporal information obtained by arterial

The magnetic anisotropy parameters of a hexacoordinate trigonally elongated Ni(II) complex with symmetry close to D3d are measured using field-dependent magnetization and High-Field and High-Frequency EPR spectroscopy (D = + 2.95 cm−1, |E/D| = 0.08 from EPR). Wave function based theoretical calculations reproduce fairly well the EPR experimental data and allows analysing the origin of the magnetic

Intramolecular electron spin exchange has been studied by X-band electron paramagnetic resonance (EPR) spectroscopy in two long-chain flexible nitroxide biradicals existing in fluid solutions in three spectroscopy-different spatial conformations as a function of temperature, solvent viscosity and polarity. Certain thermodynamic parameters of the conformational transitions were calculated from the EPR

A new resonant geometry for X-band in vivo electron paramagnetic resonance (EPR) nail dosimetry has been developed, fabricated, and tested. The dielectric-backed aperture resonator (DAR) was specifically designed for depth-limited surface spectroscopy. The DAR improves EPR sensitivity of surface samples with sub-millimeter thicknesses by at least a factor of 20 compared to other aperture resonator

Functional four-dimensional spectral–spatial electron paramagnetic imaging (EPRI) is routinely used in biomedical research. Positions and widths of EPR lines in the spectral dimension report oxygen partial pressure, pH, and other important parameters of the tissue microenvironment. Images are measured in the homogeneous external magnetic field. An application of EPRI is proposed in which the field

The nature of Ti(III) species, introduced in working models of industrial Ziegler Natta catalyst precursors, consisting of MgCl2/TiCl4 binary systems, eventually containing different Lewis basis, are studied by a combination of X- and Q-band CW and pulse EPR spectroscopy. In Ziegler Natta catalysts, Ti(III) play the double role of active catalytic species and unconventional spin probes. On the binary

Employing site-directed spin labeling (SDSL), the structure of maltose-binding protein (MBP) had previously been studied in the native state by electron paramagnetic resonance (EPR) spectroscopy. Several spin-labeled double cysteine mutants were distributed all over the structure of this cysteine-free protein and revealed distance information between the nitroxide residues from double electron–electron

We report here the synthesis and a preliminary characterization of the tetranuclear complex of formula [Ga3V(LEt)2(dpm)6], Ga3VEt, in which H3LEt = 2-Ethyl-2-(hydroxymethyl)-propane-1,3-diol and Hdpm = dipivaloylmethane, containing a single paramagnetic vanadium(III) center, from a structural, magnetic, and spectroscopic point of view. Structural characterization by X-ray diffraction evidenced that

A simple model is proposed that semi-quantitatively explains the dependence of the EPR signal intensity of adsorbed NO molecules on the adsorption value. It is assumed that there are only two types of NO adsorption sites on each facet of the microcrystal, such that only NO molecules adsorbed on one of them are active in EPR. Within the framework of this model of lattice adsorption, it is assumed that

In a typical EPR experiment, the transitions require that the static magnetic field \(B_0\) is oriented perpendicular to the microwave field \(B_1\) (perpendicular mode). This is determined by the transition rules either in the classical or in the quantum mechanical description. However, there are cases where EPR transitions are observed when \(B_0\) is oriented parallel to \(B_1\) (parallel mode)