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.

Untersuchungen über die magnetische Kernresonanz von Alkalikernen in wäßriger Lösung

1968 ◽  
Vol 23 (8) ◽  
pp. 1202-1209 ◽  
Author(s):  
O. Lutz
Keyword(s):  
Aqueous Solutions ◽  
Optical Pumping ◽  
Magnetic Moments ◽  
Water Molecules ◽  
Nuclear Magnetic Moments ◽  
Lanthanide Elements ◽  
Free Ion ◽  
Shielding Constants ◽  
The Difference ◽  
Nmr Signals

The NMR signals of the nuclei 2H, 6Li, 7Li, 23Na, 87Rb and 133Cs have been investigated in aqueous solutions. The ratios of the Larmor-frequencies of these alkali nuclei relative to 2H have been measured with high accuracy. Because the Larmor-frequencies depend on the concentration of the aqueous solutions, an extrapolatiton to vanishing concentration was made. From these ratios of Larmor-frequencies, a magnetic moment for the alkali nuclei has been derived and has been compared with the available nuclear magnetic moments from atomic beam or optical pumping experiments. The difference in the magnetic moments results from the shielding of the alkali nuclei by the water molecules around the ions. The shielding constants are: σ (Rb+) = — (2.0 ± 0.2) ·10-4 and σ (Cs+) = — (3.4 ± 0.1) · 10-4 relative to the free ion.The shift of the 133Cs NMR line as a function of the concentration of aqueous solutions of Cssalts is given in detail. The influence of the chlorides of some elements in the iron group and of some lanthanide elements on the position of the 133Cs NMR line is shown.

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.

Atomic Reference Scale for Chemical Shifts of Rubidium

1972 ◽  
Vol 27 (11) ◽  
pp. 1577-1581 ◽  
Author(s):  
O. Lutz ◽  
A. Nolle
Keyword(s):  
Infinite Dilution ◽  
Optical Pumping ◽  
Chemical Shifts ◽  
High Accuracy ◽  
Water Molecules ◽  
Solid States ◽  
Reference Scale ◽  
Shielding Constants ◽  
The Difference ◽  
Nmr Signals

Abstract With a multi-nuclei Fourier transform NMR spectrometer the ratio of the Larmor frequencies of 85Rb and 2H in a solution of RbCl in D2O has been measured with high accuracy. The concentration dependence of the 85Rb NMR signals has been determined in solutions of rubidium salts in H2O and D2O. Using this dependence, the ratio of the Larmor frequencies of the 85 Rb nuclei for infinite dilution relative to 2 H in pure D20 is given. From this a gI-factor for 85Rb has been derived and has been compared with the gI-factor of an optical pumping experiment. The difference in the gI-factors results from the shielding of the rubidium nuclei by the water molecules around the ions. The shielding constant is σ(85Rb+) = -2.11 (2) · 10-4 . This yields a general atomic reference scale for the chemical shift of rubidium in the liquid and solid states and the possibility of comparing experimental and theoretical shielding constants.

scholarly journals Isotopic effect of macro- and microelements in ecosystems

2020 ◽  
pp. 132-138
Author(s):  
О. Musich ◽  
A. Zubko ◽  
О. Demyanуuk
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Chemical Characteristic ◽  
Complex Compounds ◽  
Isotopic Effect ◽  
Biochemical Reactions ◽  
Fundamental Properties ◽  
The Difference ◽  
Living Organisms ◽  
Isotopic Effects

Isotopic effects occurring in living organisms due to metabolism are analyzed. The phenomenon of metabolism is considered in the classical sense as a combination of biochemical reactions (mainly enzyma­tic) that take place in the cells of living beings and provide the cleavage, synthesis and interconversion of complex compounds. The scope of use of natural isotopes is wide and diverse. Isotopes are carriers of information about the birth and transformation of molecules, and isotope fractionation is a chemical characteristic of a substance. Isotope metabolism consists in the intermolecular fractionation of isotopes at separate stages of biochemical reactions, namely the cleavage, synthesis and interconversion of complex compounds caused by differences in the structure and fundamental properties of isotope nuclei. It is proved that the fractionation of isotopes in chemical and biochemical reactions due to isotopic effects is based on two fundamental properties of atomic nuclei — mass and magnetic moment. The kinetic (mass-depen­ dent) isotopic effect distributes the isotopic nuclei by their masses, and the magnetic one fractionates the nuclei by their magnetic moments. The kinetic isotopic effect depends on the magnitude of the difference in the masses of isotopic molecules, temperature and the difference in the activation energies of isotopic forms. The magnetic isotope effect depends on the reaction rate in a single cell, its projection, magnetic moment and energy of electron-nuclear interaction. It is determined that the fractionation of isotopes in living organisms is that the relative content of one of the isotopes in this compound increases by reducing its content in the other. As a result, there is a fractionation of isotopes within one biological object.

Corrections to the Baseline Distortions in the OH-Stretch Region of Aqueous Solutions

1994 ◽  
Vol 48 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Wolfgang B. Fischer ◽  
Hans H. Eysel ◽  
Ole F. Nielsen ◽  
John E. Bertie
Keyword(s):  
Raman Scattering ◽  
Aqueous Solutions ◽  
Raman Spectra ◽  
Pure Water ◽  
Water Molecules ◽  
Ir Absorption ◽  
Difference Spectra ◽  
Dilute Aqueous Solutions ◽  
The Difference ◽  
Sulfuric Acid Solutions

The intensity gains or intensity losses of the OH-stretch vibrations and their changes of band shapes as observed in IR or Raman spectra of dilute aqueous solutions of carboxylic acids, amino acids, and amines were able to be simulated. The difference spectra of the type {sample solution} – {standard} x {empirical factor} displayed essentially flat baselines throughout the OH-stretch region of isotropic Raman scattering. Peaks of the solute spectra which had been hidden by the OH-stretch contour emerged from the background. At concentrations below 1 M, pure water was the standard. Distortions of the isotropic Raman spectra at higher solute concentrations (1 M to 4 M) could be mimicked by phosphoric acid or sulfuric acid solutions as standards. The influence of solutes on the reorientational motions of water molecules made baseline corrections of anisotropic Raman scattering and IR absorption of the more concentrated solutions difficult, if not impossible.

scholarly journals Fourier Transform NM R Investigations of 77Se in Aqueous Solutions

1978 ◽  
Vol 33 (9) ◽  
pp. 1025-1028 ◽  
Author(s):  
W. Koch ◽  
O. Lutz ◽  
A. Nolle
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Aqueous Solutions ◽  
Magnetic Moment ◽  
Infinite Dilution ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Recovery Method ◽  
A Value ◽  
Nmr Signals

In solutions of H2SeO3, Na2SeO3 , NaHSeO3 and Na2SeO4 in H2O NMR signals of 77Se have been observed. In these solutions chemical shifts were determined. In a 4 molal solution of Na2SeO3 the ratio of Larmor frequencies υ(77Se)/υ(1H) has been measured with a high-resolution probe. A value of the magnetic moment of 77Se in Na2SeO3 at infinite dilution in H2O is given: |μ(77Se)| = 0.533 299 6(7)μN. Relaxation times T1 have been measured by the inversion-recovery method. In a 4 molal solution of Na2SeO3 in H2O a NOE enhancement of 0.4(1) could be observed.

Long-Term Correlations In Diffusive Motion Of Water Molecules And Rare Gas Atoms In Helium And Argon Aqueous Solutions

2015 ◽  
Vol 60 (8) ◽  
pp. 757-763 ◽  
Author(s):  
V.P. Voloshin ◽  
◽  
G.G. Malenkov ◽  
Yu.I. Naberukhin ◽  
◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Rare Gas ◽  
Water Molecules ◽  
Diffusive Motion ◽  
Rare Gas Atoms

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Superior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuejian Ma ◽  
Fei Zhang ◽  
Zhaodong Chu ◽  
Ji Hao ◽  
Xihan Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Relaxation Times ◽  
Charge Trapping ◽  
Free Carrier ◽  
Carrier Dynamics ◽  
Electron Hole ◽  
Inorganic Hybrid ◽  
Diffusion Dynamics ◽  
The Difference

AbstractThe outstanding performance of organic-inorganic metal trihalide solar cells benefits from the exceptional photo-physical properties of both electrons and holes in the material. Here, we directly probe the free-carrier dynamics in Cs-doped FAPbI3 thin films by spatiotemporal photoconductivity imaging. Using charge transport layers to selectively quench one type of carriers, we show that the two relaxation times on the order of 1 μs and 10 μs correspond to the lifetimes of electrons and holes in FACsPbI3, respectively. Strikingly, the diffusion mapping indicates that the difference in electron/hole lifetimes is largely compensated by their disparate mobility. Consequently, the long diffusion lengths (3~5 μm) of both carriers are comparable to each other, a feature closely related to the unique charge trapping and de-trapping processes in hybrid trihalide perovskites. Our results unveil the origin of superior diffusion dynamics in this material, crucially important for solar-cell applications.

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