Enhancement of surface NMR by laser-polarized noble gases
Enhancement of surface NMR by laser-polarized noble gases
复制标题
通过激光偏振惰性气体增强表面核磁共振
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
A. Pines
中科院分区：
文献类型：
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作者：
T. Rõõm;S. Appelt;R. Seydoux;E. Hahn;A. Pines
在4 ~ 200k的温度范围内，证明了高表面积固体（Aerosil）表面自旋极化从激光极化氦和氙到{sup 1}H和{sup 13}C的转移。转移机制是吸附的可移动惰性气体的自旋与表面自旋之间的偶极-偶极交叉弛豫（自旋极化诱导的核Overhauser效应）。激光极化氦在4 K和10 K时对表面质子磁化强度的增强在1 ~ 2倍之间。使用激光偏振氙气，与在4.2 T场和130 k温度下的玻尔兹曼偏振相比，获得了高达20的增强因子。{copyright} {ital 1997} {ital美国物理学会}
The transfer of spin polarization from laser-polarized helium and xenon to spins such as {sup 1}H and {sup 13}C on the surface of high-surface-area solids (Aerosil) is demonstrated over a temperature range from 4 to 200 K. The transfer mechanism is dipole-dipole cross relaxation between the spins of the adsorbed mobile noble gas and the surface spins (spin-polarization-induced nuclear Overhauser effect). The enhancement of surface proton magnetization by laser-polarized helium at 4 K and 10 K is between one and twofold. Using laser-polarized xenon, enhancement factors of up to 20 were obtained when compared to the Boltzmann polarization in a field of 4.2 T and at a temperature of 130 K. {copyright} {ital 1997} {ital The American Physical Society}