Journal ArticleDOI
Nuclear magnetic relaxation by spin-rotation interaction.: Determination of spin-rotation interaction constants from nuclear magnetic shielding constants
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TLDR
In this article, the paramagnetic term of the nuclear magnetic shielding constant, σ p, was calculated from the chemical shift of nuclear resonance, which provides a general method for estimating spin-rotation interaction constants.Abstract:
Spin-rotation interaction constants, c, are calculated from the paramagnetic term of the nuclear magnetic shielding constant, σ p, using a relationship originally due to Ramsey. Calculated values show excellent agreement with experimental determinations from molecular beam measurements. Since σ p can be easily estimated from the chemical shift of the nuclear resonance this provides a general method for estimating spin-rotation interaction constants. Chemical shift anisotropies allow the components c ⊥ and c ‖ of the spin-rotation interaction tensor to be determined. Generally both components have the same sign and are of similar magnitude. The r.m.s. value of the spin-rotation interaction constant, required to calculate nuclear spin-lattice relaxation times, is not expected to differ appreciably from average values obtained from molecular beam measurements or magnetic shielding. Values for the molecular angular velocity correlation time, τ sr, calculated directly from nuclear spin-lattice relaxation times...read more
Citations
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Journal ArticleDOI
The nuclear magnetic resonance properties of chromium, molybdenum and tungsten compounds
Journal ArticleDOI
On the extended rotational diffusion models for molecular reorientation in fluids
R.E.D. McClung,R.E.D. McClung +1 more
Book ChapterDOI
Rotational Correlation Times in Nuclear Magnetic Relaxation
René T. Boeré,R. Garth Kidd +1 more
TL;DR: In this paper, rotational correlation times in nuclear magnetic relaxation are investigated. But rotational motion of molecules in the gas phase is well represented by the equipartition of energy theorem and the laws of statistical mechanics, both of which are premised on the view that, except during instantaneous collisions, the molecules move independently of one another.
References
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Journal ArticleDOI
Magnetic Shielding of Nuclei in Molecules
TL;DR: In this article, an expression for the magnetic field at a nucleus resulting from the application of an external magnetic field to a polyatomic molecule which has no resultant electron orbital or spin angular momenta in the absence of the external field is developed.
Journal ArticleDOI
Theory of Nuclear Magnetic Relaxation by Spin-Rotational Interactions in Liquids
TL;DR: The contribution of spin-rotational interactions to the nuclear magnetic relaxation of identical spin-textonehalf{} nuclei at equivalent positions in spherical liquid molecules is calculated by use of the semiclassical form of the density-operator theory of relaxation, and the result is compared with the contributions of intra-and intermolecular dipole-dipole interactions.
Journal ArticleDOI
Spin—Rotation Interaction and Magnetic Shielding in Molecules
TL;DR: In this paper, the spin-rotation constants were derived in terms of the average excitation energy, average value of (1/r3), and the charge-bond order matrix of the associated LCAO-MO functions.
Journal ArticleDOI
Vibrational Corrections to the Nuclear‐Magnetic Shielding and Spin–Rotation Constants for Hydrogen Fluoride. Shielding Scale for 19F
TL;DR: The theory of vibrational effects on the nuclear shielding and spin-rotation constants for a diatomic molecule is outlined in this article, where corrections for these effects are calculated theoretically for both 1H and 19F nuclei in the HF molecule.
Journal ArticleDOI
Proton spin-lattice relaxation in liquid water and liquid ammonia
D.W.G. Smith,Jack G. Powles +1 more
TL;DR: In this article, the authors measured the proton spin-lattice relaxation time at 20·8 Mc/s for a series of solutions of water in heavy water and solutions of ammonia in heavy ammonia for the temperature range from the melting point to the liquid-vapour critical temperature.