NMR spin-lattice relaxation rate

The 1H and 13C NMR spin-lattice relaxation rates in the nickel complex cited earlier in LSR interaction via donor atom were reduced when Gd(fod)3 was added. Gd(III) was found to bind to the two oxygen atoms of the metal complex with Gd(III) ion located... 

Fig. 2.32. Temperature dependence of the proton NMR spin-lattice relaxation rate of, 5h-(ET)2I3- From [216]...

Fig. 2.33. Angular dependence of the NMR spin-lattice relaxation rate for -(ET)2Cu[N(CN)2]Br. Prom [218]...

On the dynamics of the neutral soliton, in 1980 Nechtschein and co-workers have demonstrated the evidence for the rapid diffusion of the neutral soliton along a one-dimensional chain from the observation of the pure Overhauser effect (OE) in trans-PA using a dynamic nuclear polarization (DNP) experiment and from the l/v frequency dependence of the H NMR spin-lattice relaxation rate 7Yil [143]. These observations give quantitative estimations that the pure OE implies the condition T (iJc 10" rad/s for the... 

The B-coefficients obtained from viscosity and NMR signal relaxation rates pertain to dilute solutions (they are the limiting slopes towards infinite dilution). However, an equation of the form of Eq. (3.6) for NMR spin-lattice relaxation rates holds up to fairly large concentrations. Chizhik (1997) reported values of relative water molecule reorientation times Tri/Trw at 22 °C, being <1 for Br , I, NH4+, NOs, and Ns , 1.0 for K+, and >1 for Li+, Na+, Mg +, Ca +, Sr +, Ba +, F , CH, H3O+, S04 , and COs, in more or less agreement with the signs of the Bnmr in dilute solutions. Table 3.1. 

P. F. Meier, NMR Spin-Lattice Relaxation Rates in Cuprates , J. Supercond. 

NMR relaxation of liquids such as water in porous solids has been studied extensively. In the fast exchange regime, the spin-lattice relaxation rate of water in pores is known to increase due to interactions with the solid matrix (so-called surface relaxation ). In this case, T) can be described by Eq. (3.5.6) ... 

The convenient NMR observables depend on the characteristics of the system studied, but generally the protons of the liquid are readily detected. The apparent NMR linewidths are often determined by the magnetic susceptibility inhomogeneities in the sample and do not directly reflect the dynamics of the liquid. This report will focus largely on theoretical approaches to understand the spin-lattice relaxation rate constants for both classes of microporous materials. The magnetic held dependence of the spin-lattice relaxation rate constant generally provides a useful dynamical characterization of the liquid and often a structural characterization of the confining media. 

We have identified HFB as an ideal reporter molecule [224]. Symmetry provides a single narrow F NMR signal and the spin lattice relaxation rate is highly... 

Water mobility from molecular reorientation and diffusion. Evidence for the motion of the water molecules in crystal structures is typically provided by XH NMR (Davidson and Ripmeester, 1984). At very low temperatures (<50 K) molecular motion is frozen in so that hydrate lattices become rigid and the hydrate proton NMR analysis suggests that the first-order contribution to motion is due to reorientation of water molecules in the structure the second-order contribution is due to translational diffusion. 2H NMR has been also used to measure the reori-entational rates of water and guest molecules in THF hydrate (Bach-Verges et al., 2001). Spin lattice relaxation rates (fy) have been measured during THF hydrate... 

NMR line is proportional to the local electronic susceptibility, and in such a situation, it will be very different for the different sites. For a Cs neighboring a C d, the local electronic susceptibility is dominated by the excitations of the singlet, leading to a strong temperature dependence for the S line clearly seen in Fig. 10. On the contrary, the NS line does not shift, according to the temperature-independent susceptibility characteristic of a metal. A similar contrast is found in the spin-lattice relaxation rate 1/T, for each line. The relatively small number of singlets explains that macroscopic probes, such as ESR, only detect the predominantly metallic character. 

Abstract Spatially-resolved NMR is used to probe antiferromagnetism in the vortex state of nearly optimally doped high-rc cuprate H2Ba2CuC>6+a (Tc = 85 K). The broadened 205Tl-spectra below 20 K and the temperature dependence of the enhanced nuclear spin-lattice relaxation rate 205 Tfl at the vortex core region indicate clear evidences of the antiferromagnetic order inside the vortex core ofTl2Ba2Cu06+J. 

Recent experimental [12,13] and theoretical [14] NMR studies have established that the frequency dependence of spin-lattice relaxation rate 7)-1 in the... 

NMR relaxation studies can provide detailed information pertaining to the internal dynamics in proteins on a time scale from milliseconds to picoseconds (Section 1.6.2.). The 1SN, l3C and 2H spin-lattice relaxation rate (1/Tt) and heteronuclear NOE s are sensitive to high frequency motion (108-1012 s 1), while the spin-spin relaxation rate (1/T2) is a function of much slower processes. 

One of the classical NMR methods used to determine molecular correlation times is provided by spin-lattice relaxation experiments. The spin-lattice relaxation rate 1 /T is determined by transitions among the Zeeman levels. For a liquid, the expression for the spin-lattice relaxation rate [81] is... 

Here, K% is a constant related to the NMR coupling constant,. S 2 is the spectral density associated with the second-rank orientational correlation function g2(f). If g2(f) is an exponential function, such as in rotational diffusion, Eq. (16) reduces to the famous Bloembergen-Purcell-Pound (BPP) expression for the spin-lattice relaxation rate [81,82]. 

In this work we will be specially concerned with intra- and interchain contact and dipolar interactions and will ignore the above-mentioned other terms, despite the fact that they may be relevant in particular cases. We should also make clear that the NMR technique gives the total spin-lattice relaxation rate over all q vectors. Therefore, it will be necessary to make a thorough analysis of the data to extract the relevant components. On the other hand, a complete theory of the spin-lattice relaxation rate in organic conductors is still lacking. In our description we try to point out some of the main features, the temperature and field dependence. 

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