IUPAC - relaxation time (R05287)

relaxation time

https://doi.org/10.1351/goldbook.R05287

In magnetic resonance spectroscopy the longitudinal relaxation time, $T_{1}$ , is associated with spin-lattice relaxation, and the transverse relaxation time, $T_{2}$ , with spin-spin relaxation. The definitions are: $\frac{d M_{z}}{d t} = - \frac{M_{z} - M_{z, e}}{T_{1}}$ and $\frac{d M_{x}}{d t} = - \frac{M_{x}}{T_{2}}$ , where $M_{z}$ and $M_{x}$ are the components of magnetization parallel and perpendicular to the static field $B$ and the subscript e denotes the equilibrium value.
Source:
Green Book, 2^nd ed., p. 25 [Terms] [Book]
In a chemical reaction, the time, $τ$ , in which a concentration perturbation falls to $\frac{1}{e}$ of its initial value.
Source:
Green Book, 2^nd ed., p. 55 [Terms] [Book]

See also:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 185 [Terms] [Paper]

Citation: 'relaxation time' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.R05287 RIS BibTex EndNote

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relaxation time