Proton spin-lattice time water

Figure 6. The proton spin-lattice time, Tt, in water as a function of temperature and density (Ref. 11. The supercritical values are at temperatures greater than...

J. C. Hindman, A. Svirmickas, M. Wood 1973, (Relaxation processes in water. A study of the proton spin-lattice relaxation time),/. Chem. Phys. 59 (3), 1517— 1522. 

Fig. 1. Magnetic field dependences of the proton spin-lattice relaxation time of water in Bioran B30 and Vycor glasses at temperatures above 27°C and below the temperature where the non-surface water freezes ( —25°C and —35°C). The solid lines represent the power law in the Larmor frequency with an exponent of 0.67 (34).

The proton spin-lattice relaxation times for solvent water are strongly perturbed if the water is in rapid exchange with a paramagnet. In particular, Mn is a strong relaxer for water protons and thus nuclear magnetic resonance (NMR) spectroscopy provides a sensitive probe for the presence of exchangeable water molecules bound to Mn in Mn proteins. 

Figure 10. Proton spin lattice relaxation time dependence vs. temperature for different water contents (NMR, 60 MHz)...

The proton spin-lattice relaxation time, Tj, of water was measured using this probe as a function of pressure and temperature (see Fig. 4.30). ° The study focused on the supercritical region (above = 374 °C) where the spin-... 

To further probe the role of hydration water in the high-T crossover, we measure the NMR proton spin-lattice relaxation time constant Ti of the lysozyme-water system with h = 0.3 in the interval 275K < T < 355K (Fig. 3b). Figure 3b also shows T for pure bulk water. Note that the hydration water Ti is characterized by two contributions, one coming from the hydration water protons (on the order of seconds, as in bulk water, Tih) and the other from the protein protons (on the order of 10 ms Tip). Figure 3b also shows that, as T increases, the bulk water Ti follows the VFT law across the entire temperature range, but the Tn, exhibits two... 

Fig. 14. Measured water spin-lattice relaxation rates of a hydrated mortar at w/c = 0.38 as a function of the proton Larmor frequency, for different duration of hydration Oh 34 min ( ), 7h 27 min (O), 8h 45 min ( ), and 9h 40 min ( x ), upwards. The insert represents the data obtained after a hydration time of lOh 32 (+), the labels for the two axis are equivalent to those of the main figure. The continuous lines correspond to the best fits to the theory.

Dynamic processes such as fluctuational motions of water molecules can be studied from the spin-lattice relaxation times of proton nuclear resonance . In the presence of highly mobile H atoms, the separation of the proton resonance disappears and the remaining signal sharpens as for isotropic liquids. Furthermore, the frequencies of H2O librations (see Sect. 4.4) can be computed . ... 

---