scholarly journals Search for a Primary Isotopic Effect on the Magnetic Shielding of the Rubidium and Cadmium Isotopes

1973 ◽  
Vol 28 (3-4) ◽  
pp. 484-486
Author(s):  
H. Krüger ◽  
O. Lutz ◽  
A. Nolle ◽  
A. Schwenk ◽  
G. Stricker
Keyword(s):  
Aqueous Solutions ◽  
Optical Pumping ◽  
High Accuracy ◽  
Isotopic Effect ◽  
Magnetic Shielding ◽  
Nmr Method ◽  
Free Atoms ◽  
Limits Of Error

AbstractThe ratios of the gI-factors of 85Rb and 87Rb and of 111Cd and 113Cd have been measured in aqueous solutions of salts by the NMR method with high accuracy. A comparison with the same ratios measured by optical pumping techniques in free atoms shows agreement within the limits of error of 2.3 · 10-6 in the case of rubidium and of 3 · 10-7 in the case of cadmium: No difference in the magnetic shielding between the isotopes is observable.

Fourier-Kernresonanzuntersuchungen an 10 B und 11 B in wäßriger Lösung / Fourier Transform NMR Studies of 10 B and 11 B in Aqueous Solutions

1975 ◽  
Vol 30 (8) ◽  
pp. 955-958 ◽  
Author(s):  
B. W. Epperlein ◽  
. Lutz ◽  
A. Schwenk
Keyword(s):  
Fourier Transform ◽  
Aqueous Solutions ◽  
Hyperfine Interaction ◽  
Magnetic Moment ◽  
Ground State ◽  
Magnetic Shielding ◽  
Nmr Studies ◽  
Nmr Method ◽  
Atomic Ground State ◽  
Nmr Signals

Abstract The ratios of the Larmor frequencies of 10 B and 2 H and of 11 B and 10 B have been measured with the NMR method and a magnetic moment has been calculated for 10 B in the B (OH)4- -ion. For this, an investigation of the dependence of the NMR signals of 10 B and 2 H on the concentration of some boron salts in solutions of H2O and D2O was necessary. Using hyperfine interaction constants from literature, the hyperfine structure anomaly 10 ∆ 11 of boron in the 2 P1/2 atomic ground state has been calculated. A difference in the magnetic shielding between the isotopes 10 B and 11 B in different compounds could not be detected.

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.

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.

scholarly journals 109Ag Nuclear Magnetic Resonance Studies of Organic and Inorganic Silver Complexes

1976 ◽  
Vol 31 (12) ◽  
pp. 1532-1538 ◽  
Author(s):  
K. Jucker ◽  
W. Sahm ◽  
A. Schwenk
Keyword(s):  
Aqueous Solutions ◽  
Chemical Exchange ◽  
Chemical Shifts ◽  
Linear Functions ◽  
Silver Salts ◽  
Two Samples ◽  
Chemical Shift Data ◽  
Limits Of Error ◽  
Ethyl Amine ◽  
Good Agreement

AbstractThe NMR lines of 109Ag have been investigated in solutions of several silver salts in acetonitrile, propionitrile, pyridine, and ethylenediamine, and also in aqueous solutions of Na2S2O3 and ethyl-amine. In these solvents the Ag+ -ions form one or several complexes. In any case a single NMR line was to be detected, i. e. a rapid chemical exchange between different complexes in a sample may be assumed. The concentration dependence of the chemical shifts was determined with high accuracy for these solutions. From these results the chemical shift data of some defined complexes were derived. The chemical shifts of mixtures of AgCl and AgBr and also of AgCl and Agl dissolved in 70% aqueous solution of ethylamine are linear functions of the anions mole fraction. In two samples of AgNO3 dissolved in organic solvents, the ratio υ(109Ag)/υ(107Ag) = 1.149 640 (1) was measured in good agreement with the value from silver salts in aqueous solutions; i. e. no primary isotopic effect was to be detected within these limits of error (0.9 ppm).

A single point NMR method for an instantaneous determination of the moisture content of wood

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Maks Merela ◽  
Primož Oven ◽  
Igor Serša ◽  
Urša Mikac
Keyword(s):  
Moisture Content ◽  
Wood Sample ◽  
Single Point ◽  
Gravimetric Method ◽  
High Accuracy ◽  
Proton Density ◽  
Nmr Method ◽  
Free Induction ◽  
The Relationship

Abstract Nuclear magnetic resonance (NMR) enables an instantaneous determination of the proton density in liquids and is thus convenient for determining the moisture content (MC) of wood. We demonstrated that the MC of a wood sample can be determined instantaneously on the basis of its mass (m) and the amplitude of its NMR free-induction-decay (FID) signal. The measurement is based on the assumption that the only liquid in the wood is water and that the relationship between the amplitude of the FID signal (S) and the mass of the water (m w ) in the sample is linear, i.e., S=k m w +k′ (m-m w ), and can be precisely calibrated for a given NMR probe and NMR spectrometer setup (in our case k=105 AU g-1 and k/k′ =34). With the FID signal converted into the mass of water, the MC is calculated as: MC=(S-m k′)/(m k-S). After the initial calibration of the FID signal with respect to the content of water, the correctness of the method was verified on samples of different wood species with various MCs. The results confirmed that the proposed method is comparable in terms of accuracy and reliability to the gravimetric method, regardless of the species of wood. As the method is instantaneous, it might become the method of choice in applications where a short measurement time combined with a high accuracy is demanded.

11B and 10B NMR Investigations in Aqueous Solutions

1986 ◽  
Vol 41 (5) ◽  
pp. 737-742 ◽  
Author(s):  
R. Balz ◽  
U. Brändle ◽  
E. Kämmerer ◽  
D. Köhnlein ◽  
O. Lutz ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Isotope Effect ◽  
Chemical Shifts ◽  
Relaxation Mechanism ◽  
Magnetic Shielding ◽  
Solvent Isotope Effect ◽  
Weighted Averages ◽  
Dilute Aqueous Solutions ◽  
Ph Dependent ◽  
Solvent Isotope

11B NMR chemical shifts and linewidths have been measured in very dilute aqueous solutions of boric acid and borates. The results can be explained bv taking pH dependent weighted averages over the species B(OH)3 and B(OH)4−. The11B−10B primary isotope effect on the magnetic shielding is smaller then 3 · 10-8. The H2O - D2O solvent isotope effect on T1 has been established for 11B and 10B in the species mentioned, and from the ratios of T1 the quadrupolar origin of the relaxation mechanism has been inferred.

scholarly journals Внутридоплеровские резонансы, обусловленные фотоионизацией атомов в тонких газовых ячейках

2022 ◽  
Vol 130 (3) ◽  
pp. 353
Author(s):  
А.Ч. Измайлов
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Optical Pumping ◽  
Photoionization Cross Section ◽  
High Accuracy ◽  
High Resolution Spectroscopy ◽  
Atoms And Molecules ◽  
Optical Resonances ◽  
A Cell ◽  
Ionization Processes

By analogy with the well-tested method of high-resolution spectroscopy in thin gas cells for the processes of optical pumping of atoms, this work shows the possibility of detecting narrow sub-Doppler optical resonances caused directly by straight photoionization of atoms (or molecules) in such cells. The structure of the established nontrivial resonances substantially depends on the probability of photoionization of atoms and dimensions of such a cell, the internal thickness of which is many times smaller than its diameter. Of particular interest is the broadening of the considered sub-Doppler resonances, which is determined directly by the photoionization cross section of atoms and the intensity of radiation causing ionization. Under certain conditions, such photoionization broadening can be measured experimentally with high accuracy, as a result of which it is possible to obtain new important information about ionization processes in atoms and molecules.

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