期刊
EMAGRES
卷 5, 期 3, 页码 1395-1409出版社
WILEY
DOI: 10.1002/9780470034590.emrstm1369
关键词
ZULF NMR; zero-field NMR; field-cycling NMR; hyperpolarization; PHIP; spin-spin coupling; J-coupling; J-spectroscopy; atomic magnetometry; alkali vapor cell magnetometry
类别
资金
- U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering [DE-AC02-05CH11231]
- National Science Foundation [CHE-1308381, DGE-1106400]
- Direct For Mathematical & Physical Scien [1308381] Funding Source: National Science Foundation
This article presents the basic principles and methodology used in modern implementations of zero-to ultralow-field NMR (ZULF NMR), with emphasis on the case where spin evolution is detected directly in the ZULF environment. In contrast to conventional high-field NMR, ZULF NMR allows for measurement of spin-spin interactions 'in their natural environment' free of truncation by dominant coupling to applied magnetic fields. However, the absence of a large applied magnetic field means that spin precession frequencies and equilibrium spin polarization-related to the sensitivity of inductive detection and to the magnitude of the measurable magnetization, respectively-are dramatically lower than in the high-field case. ZULF NMR thus requires the use of alternative detectors such as atomic magnetometers, along with the production of nonequilibrium spin polarization as prepared by, for example, prepolarization in a permanent magnet or parahydrogen-induced polarization. Nevertheless, ZULF NMR permits particularly high-resolution measurement of spin-spin couplings due to the high absolute magnetic field homogeneity and the absence of certain relaxation pathways such as chemical shift anisotropy or susceptibility-induced gradients. Furthermore, ZULF NMR is capable of directly detecting spin interactions that do not commute with the Zeeman Hamiltonian and are thus unobservable with high-field NMR.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据