NEW PERSPECTIVES OF NMR IN ULTRAHIGH STATIC MAGNETIC-FIELD GRADIENTS
NEW PERSPECTIVES OF NMR IN ULTRAHIGH STATIC MAGNETIC-FIELD GRADIENTS
复制标题
DOI：
10.1016/0022-3093(94)90563-0
复制
发表时间：
1994-09-01
影响因子：
3.5
通讯作者：
TOLLE, A
中科院分区：
文献类型：
--
作者：
CHANG, IY;FUJARA, F;TOLLE, A
磁场梯度核磁共振（NMR）受激回波实验测量中间散射函数S（Q，t）的非相干（或自）部分，其类似于具有“广义”散射矢量Q = γ.g. τ（γ是旋磁比，g是磁场梯度，τ是演化时间）的[exp[ -iQr（0）] exp [iQr（t）]]。随着静态磁场梯度高达约180 T/m，其原型最近已安装在美因茨，Q值高达> 10（-2）埃（-1）变得可访问。本文的第一部分着重于这种技术发展的细节，并指出密切的类比与非相干中子散射。在第二部分中，这种梯度核磁共振的巨大的新的可能性是通过收集的最新的应用：测量小的自扩散系数低至约10（-15）m（2）s（-1）在过冷液体和分子晶体，长链聚合物动力学，限制扩散系统中的有限介观几何形状和分形结构的异常扩散。
The magnetic field gradient nuclear magnetic resonance (NMR) stimulated echo experiment measures the incoherent (or self) part of the intermediate scattering function S(Q, t) similar to [exp[ -iQr(0)] exp [iQr(t)]] with a 'generalized' scattering vector Q = gamma.g.tau (gamma is the gyromagnetic ratio, g is the magnetic field gradient, tau is the evolution time). With ultrahigh static field gradients up to approximate to 180 T/m, a prototype of which has recently been installed in Mainz, Q-values up to > 10(-2) Angstrom(-1) become accessible. The first part of the paper focusses on details of this technical development and points out the close analogy with incoherent neutron scattering. In the second part, the enormous new possibilities of this kind of gradient NMR are demonstrated through a collection of most recent applications: the measurement of small self-diffusion coefficients down to about 10(-15) m(2) s(-1) in supercooled liquids and in molecular crystals, long chain polymer dynamics, restricted diffusion in systems of confined mesoscopic geometries and anomalous diffusion on fractal structures.