Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
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DOI：
10.1016/j.cplett.2014.04.013
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发表时间：
2014-05-20
影响因子：
2.8
通讯作者：
Jannin, Sami
中科院分区：
文献类型：
--
作者：
Bornet, Aurelien;Milani, Jonas;Jannin, Sami
溶解超极化动态核极化通常是通过在1.2 K和3.35 T下单色微波照射嵌入玻璃中的自由基的ESR谱来实现的。Hovav等人（2014）最近表明，通过使用频率调制（而不是单色）微波辐射，可以在10-50 K的温度范围内在3.35 T下改善DNP。我们在这封信中表明，在1.2 K和6.7 T的溶解-DNP条件下也是如此。我们证明了使用调频微波辐射的许多优点：更高的极化，更快的建设率，更低的自由基浓度，更少的顺磁展宽，更有效的交叉极化，和更少的临界频率调整。(C)2014作者由爱思唯尔公司出版
Hyperpolarization by Dissolution Dynamic Nuclear Polarization is usually achieved by monochromatic microwave irradiation of the ESR spectrum of free radicals embedded in glasses at 1.2 K and 3.35 T. Hovav et al. (2014) have recently shown that by using frequency-modulated (rather than monochromatic) microwave irradiation one can improve DNP at 3.35 T in the temperature range 10-50 K. We show in this Letter that this is also true under Dissolution-DNP conditions at 1.2 K and 6.7 T. We demonstrate the many virtues of using frequency-modulated microwave irradiation: higher polarizations, faster buildup rates, lower radical concentrations, less paramagnetic broadening, more efficient cross-polarization, and less critical frequency adjustments. (C) 2014 The Authors. Published by Elsevier B.V.