DYNAMIC NUCLEAR-POLARIZATION WITH A CYCLOTRON-RESONANCE MASER AT 5-T

被引：418

作者：

BECERRA, LR

GERFEN, GJ

TEMKIN, RJ

SINGEL, DJ

GRIFFIN, RG

机构：

[1] MIT,DEPT CHEM,CAMBRIDGE,MA 02139

[2] MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139

[3] HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138

来源：

PHYSICAL REVIEW LETTERS | 1993年 / 71卷 / 21期

关键词：

D O I：

10.1103/PhysRevLett.71.3561

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

DNP (dynamic nuclear polarization) experiments at 5 T are reported, in which a cyclotron resonance maser (gyrotron) is utilized as a 20 W, 140 GHz microwave source to perform the polarization. MAS (magic angle spinning) NMR spectroscopy with DNP has been performed on samples of polystyrene doped with the free radical BDPA (alpha,gamma-bisdiphenylene-beta-phenylallyl) at room temperature. Maximal DNP enhancements of approximately 10 for H-1 and approximately 40 for C-13 are observed and are considerably larger than expected. The DNP and spin relaxation mechanisms that lead to these enhancements at 5 T are discussed.

引用

页码：3561 / 3564

页数：4

共 14 条

[1]

ABRAGAM A, 1982, NUCLEAR MAGNETISM OR, pCH6

[2]

AFERWORKI M, 1992, MACROMOLECULES, V25, P4097

[3]

AFERWORKI M, 1992, MACROMOLECULES, V25, P4084

[4]

AFERWORKI M, 1992, MACROMOLECULES, V25, P4100

[5]

AFERWORKI M, 1992, MACROMOLECULES, V25, P4092

[6]

BARTHIA P, 1984, MILLIMETER WAVE ENG, P52

[7]

BELLEW B, UNPUB

[8]

BENFORD J, 1992, HIGH POWER MICROWAVE

[9] A QUANTITATIVE INVESTIGATION OF THE DYNAMIC NUCLEAR-POLARIZATION EFFECT BY FIXED PARAMAGNETIC CENTRA OF ABUNDANT AND RARE SPINS IN SOLIDS AT ROOM-TEMPERATURE [J].

DUIJVESTIJN, MJ ;

WIND, RA ;

SMIDT, J .

PHYSICA B & C, 1986, 138 (1-2) :147-170

[10]

Mims W. B., 1972, ELECTRON PARAMAGNETI

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