39K, 40K and 41K Nuclear Magnetic Resonance Studies

1974 ◽  
Vol 29 (12) ◽  
pp. 1754-1762 ◽  
Author(s):  
W. Sahm ◽  
A. Schwenk
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Moments ◽  
Relaxation Times ◽  
Isotopic Effect ◽  
Water Molecules ◽  
Potassium Salts ◽  
Rare Isotope ◽  
Resonance Frequencies ◽  
First Time ◽  
Limits Of Error

The NMR lines of 39K and 41K have been investigated in solutions of many potassium salts in H2O, D2O, methanol and ethylenediamine and also in solid potassium halides. The NMR signal of the rare isotope 40K was detected for the first time. The ratio of the Larmor frequencies of 39K and 41K has been measured in various samples: υ(30K)/υ(41K) =1.821873 1 (9). No primary isotopic effect was to be detected within these limits of error (0.5 ppm). The concentration dependence of the chemical shift of the 39K resonance frequencies was determined. Using this dependence, the ratios of the Larmor frequencies of the nuclei 39K, 40K, and 41K for infinite dilution relative to the resonance frequency of 2H in D2O are given. The magnetic moments of the 39K+, 40K+, and 41K+ ions purely surrounded by water molecules are μ(39K+) =0.390 952 9 (24)μN, μ(40K+) = -1.296 262(9)μN , μ(41K+) =0.214 588 4 (13) μN without diamagnetic corrections. Comparison of these values with the results of atomic beam magnetic resonance experiments yields the hyperfine structure anomalies of all pairs of potassium isotopes and also the shielding of potassium nuclei by water molecules around the ions; the shielding constant is σ* (K+ in H2O vs. K atom) = - 0.000 105 2(8). For the liquid samples the relaxation times T2 and for the solid ones the relaxation times T2 and the line widths are given.

107Ag and 109Ag Nuclear Magnetic Resonance Studies of Ag+ Ions in Aqueous Solutions

1973 ◽  
Vol 28 (11) ◽  
pp. 1753-1758 ◽  
Author(s):  
C.-W. Burges ◽  
R. Koschmieder ◽  
W. Sahm ◽  
A. Schwenk
Keyword(s):  
Aqueous Solutions ◽  
Infinite Dilution ◽  
Magnetic Moments ◽  
Relaxation Times ◽  
Isotopic Effect ◽  
Water Molecules ◽  
Resonance Frequencies ◽  
Beam Experiment ◽  
The Difference ◽  
Limits Of Error

The NMR lines of 107Ag and 109Ag have been investigated in aqueous solutions of AgF, AgNO3, and AgClO4. The ratio of the Larmor frequencies of 109Ag and 107Ag has been measured in various samples: ν(109Ag)/ν(107Ag) = 1.149 639 7 (8). No primary isotopic effect was to be detected within these limits of error (0.7 ppm). This ratio yields the hyperfine structure anomaly 107⊿109 = − 0.004127 7(7). The concentration dependence of the chemical shift of the 107Ag and 109Ag resonance frequencies was determined. Using this dependence, the ratios of the Larmor frequencies of the 107Ag and 109Ag nuclei for infinite dilution relative to the resonance frequency of 73Ge in GeCl4 are given. The magnetic moments of the 107Ag+ and 109Ag+ ions merely surrounded by water molecules are μ(107Ag+) = − 0.113 045 3(9) μN and μ(109Ag+) = − 0.129 961 5(10) μN without diamagnetic corrections. These values are compared with the result of an atomic beam experiment, the difference of the moments is due to the shielding of the silver nuclei by water molecules around the ions. The shielding constant is σ* (Ag+ in H2O vs. Ag atom) = − 0.000 94(17). Preliminary values of the relaxation times are given.

scholarly journals Magnetic Resonance Imaging of Water in Flower Buds of Blueberry

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 339-341 ◽  
Author(s):  
Lisa J. Rowland ◽  
Dehua Liu ◽  
Merle M. Millard ◽  
Michael J. Line
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Vaccinium Corymbosum ◽  
Water Molecules ◽  
Chilling Requirement ◽  
Resonance Imaging ◽  
Flower Buds ◽  
Restricted Form ◽  
Magnetic Resonance Imaging Mri

Dormant and chilled highbush blueberry (Vaccinium corymbosum L.) flower buds were examined by magnetic resonance imaging (MRI). T2 relaxation times of water molecules were too short to create images from flowers within buds that were dormant and had received no chilling, but they were sufficiently long to create images from buds that had their chilling requirement satisfied. To explain the change in relaxation times, we concluded that water is present in a motionally restricted form in flowers of dormant blueberry buds and in a freer form in flowers of buds after the chilling requirement has been satisfied. T2 values for chilled blueberry buds indicated that one population of water molecules with a detectable T2 time was present in flowers of chilled buds with a relaxation time of ≈8 to 15 ms.

scholarly journals Intracellular and Extracellular Spaces of Normal Adult Rat Brain Determined from the Proton Nuclear Magnetic Resonance Relaxation Times

1987 ◽  
Vol 7 (5) ◽  
pp. 552-556 ◽  
Author(s):  
Munetaka Haida ◽  
Masahiro Yamamoto ◽  
Hideshi Matsumura ◽  
Yukito Shinohara ◽  
Minoru Fukuzaki
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Rat Brain ◽  
Brain Tissue ◽  
Relaxation Times ◽  
Proton Nuclear Magnetic Resonance ◽  
Water Molecules ◽  
Normal Rat ◽  
Rat Brain Tissue ◽  
Nuclear Magnetic

The nuclear magnetic resonance method was used to investigate the state of water molecules in normal rat brain tissue in vitro. The transverse magnetization decay curve (TMDC) of the fresh brain tissue of adult rats (8- or 10-weeks-old) was biexponential, which could be interpreted in terms of two distinct transverse relaxation times ( T2). Several factors that may affect the TMDC are discussed. It was concluded that the fast and slow components of T2 correspond to those of the water molecules of the intracellular and the extracellular spaces of normal rat brain tissue, respectively.

Investigation of the nuclear magnetic resonance spectra of potassium ions in aqueous solutions and estimation of the magnetic moment of the nucleus 39K

2021 ◽  
pp. 3-8
Author(s):  
Yuryi I. Neronov ◽  
Anton N. Pronin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Moment ◽  
Potassium Ions ◽  
Potassium Salts ◽  
Nuclear Magnetic Resonance Spectra ◽  
Resonance Frequencies ◽  
Living Tissues ◽  
Nmr Signals ◽  
Nuclear Magnetic

The problem of increasing the accuracy of determining the magnetic moment of the potassium 39K nucleus, which is used in studies of the norm and pathology of living tissues by nuclear magnetic resonance methods, is considered. The paper presents experimental results for determining the resonance frequency ratio of water protons and 39K nuclei for KCl and KNO3 solutions at concentrations from 0.5 to 2 mol/kg of water. NMR signals from water protons and potassium nuclei were recorded simultaneously, which minimizes random and systematic errors in determining the ratio of the resonance frequencies to units of the eighth sign. When extrapolating the content of potassium salts in water to zero concentrations for single ions in water, it was determined 21.4300226(10). Using the known data for the magnetic moment of the proton and the data for proton shielding in water, we obtained 0.390962111(18). Shielding of potassium ions in water was previously calculated in the work of Antisera and others. When using these data on the shielding of potassium ions in water, the magnetic moment of the potassium core was obtained 0.391471(8). The comparison of the new result for μ(39K) with the data of previous works is discussed.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Quantification of T1, T2 relaxation times from Magnetic Resonance Fingerprinting radially undersampled data using analytical transformations

2021 ◽  
Vol 80 ◽  
pp. 81-89
Author(s):  
Nikolaos Dikaios ◽  
Nicholas E. Protonotarios ◽  
Athanasios S. Fokas ◽  
George A. Kastis
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Times ◽  
T2 Relaxation ◽  
Undersampled Data

scholarly journals Revealing noncollinear magnetic ordering at the atomic scale via XMCD

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fridtjof Kielgast ◽  
Ivan Baev ◽  
Torben Beeck ◽  
Federico Pressacco ◽  
Michael Martins
Keyword(s):  
Ground State ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Atomic Scale ◽  
Angle Of Incidence ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Magnetic Sublattices

AbstractMass-selected V and Fe monomers, as well as the heterodimer $${\text{Fe}}_1{\text{V}}_1$$ Fe 1 V 1 , were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.

scholarly journals Microresonators and Microantennas—Tools to Explore Magnetization Dynamics in Single Nanostructures

2021 ◽  
Vol 7 (2) ◽  
pp. 28
Author(s):  
Hamza Cansever ◽  
Jürgen Lindner
Keyword(s):  
Magnetic Resonance ◽  
Spin Wave ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Relaxation Times ◽  
Magnetic Nanostructures ◽  
Microwave Frequency ◽  
Direct Access ◽  
Magnetization Dynamics ◽  
G Factor

The phenomenon of magnetic resonance and its detection via microwave spectroscopy provide insight into the magnetization dynamics of bulk or thin film materials. This allows for direct access to fundamental properties, such as the effective magnetization, g-factor, magnetic anisotropy, and the various damping (relaxation) channels that govern the decay of magnetic excitations. Cavity-based and broadband ferromagnetic resonance techniques that detect the microwave absorption of spin systems require a minimum magnetic volume to obtain a sufficient signal-to-noise ratio (S/N). Therefore, conventional techniques typically do not offer the sensitivity to detect individual micro- or nanostructures. A solution to this sensitivity problem is the so-called planar microresonator, which is able to detect even the small absorption signals of magnetic nanostructures, including spin-wave or edge resonance modes. As an example, we describe the microresonator-based detection of spin-wave modes within microscopic strips of ferromagnetic A2 Fe60Al40 that are imprinted into a paramagnetic B2 Fe60Al40-matrix via focused ion-beam irradiation. While microresonators operate at a fixed microwave frequency, a reliable quantification of the key magnetic parameters like the g-factor or spin relaxation times requires investigations within a broad range of frequencies. Furthermore, we introduce and describe the step from microresonators towards a broadband microantenna approach. Broadband magnetic resonance experiments on single nanostructured magnetic objects in a frequency range of 2–18 GHz are demonstrated. The broadband approach has been employed to explore the influence of lateral structuring on the magnetization dynamics of a Permalloy (Ni80Fe20) microstrip.

Dielectric and nuclear magnetic resonance study of the hydrate of sulphur hexafluoride

1968 ◽  
Vol 46 (10) ◽  
pp. 1683-1690 ◽  
Author(s):  
Y. A. Majid ◽  
S. K. Garg ◽  
D. W. Davidson
Keyword(s):  
Magnetic Resonance ◽  
Lattice Structure ◽  
Nuclear Magnetic Resonance Study ◽  
Water Molecules ◽  
Activation Entropy ◽  
Sulphur Hexafluoride ◽  
Rigid Lattice ◽  
Second Moment ◽  
Resonance Behavior ◽  
Arrhenius Energy

In its dielectric and proton magnetic resonance behavior (except T1) the clathrate hydrate of SF6 is similar to ice I. Reorientation of water molecules appears to be little affected by the guest SF6 molecules and probably depends on the diffusion of rotational Bjerrum defects formed in numbers intrinsic to the lattice structure. The Arrhenius energy and activation entropy for dielectric relaxation are 12.3 + 0.5 kcal mole−1 and 6.8 + 2.0 cal deg−1 mole−1, respectively. The proton rigid-lattice second moment is 32.8 ± 0.5 G2 at −180 °C. The 19F second moment agrees with the value calculated for rapid isotropic rotation of SF6 molecules in the large cages only. Diffusion of water molecules in the hydrate is slower than in ice, which suggests that diffusion in ice occurs by migration of interstitial molecules through the channels in ice rather than by migration of lattice vacancies.

The solution conformation of prostacyclin as determined by high field proton magnetic resonance techniques

1980 ◽  
Vol 58 (10) ◽  
pp. 974-983 ◽  
Author(s):  
George Kotovych ◽  
Gerdy H. M. Aarts ◽  
Tom T. Nakashima ◽  
Glen Bigam
Keyword(s):  
Magnetic Resonance ◽  
Correlation Time ◽  
Proton Magnetic Resonance ◽  
Double Resonance ◽  
Relaxation Times ◽  
Segmental Motion ◽  
Solution Conformation ◽  
Nmr Spectrum ◽  
H Nmr ◽  
The Difference

The proton magnetic resonance (1H nmr) spectrum at 400 MHz of prostacyclin at pH 10.4 in glycine buffer has been completely analyzed utilizing homonuclear double resonance, inversion recovery, and difference nOe experiments. The spectral analysis shows that the two protons at C-4 are non-equivalent even though they are removed from the asymmetric centres at C-8 and C-9 by five bonds. The difference nOe measurements verify the configuration at C-5.Proton longitudinal relaxation times (T1) were measured at 400 and 200 MHz. From the T1 frequency dependence, effective rotational correlation times ranging from 2.3 × 10−10 to 3.0 × 10−10 s were calculated for H-5, H-9, H-11, and H-15. This indicates that the portion of the molecule encompassed by these protons has a longer correlation time than is observed for the C-2 and the C-17 to C-19 protons, for which the average correlation time is 1.2 × 10−10 s. Hence the aliphatic side chains have more segmental motion.

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