The decay of the refocused Hahn echo in DEER experiments
The decay of the refocused Hahn echo in DEER experiments
复制标题
DEER 实验中重新聚焦哈恩回波的衰减
DOI：
--
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
D. Goldfarb
中科院分区：
文献类型：
--
作者：
Thorsten Bahrenberg;Samuel M. Jahn;A. Feintuch;S. Stoll;D. Goldfarb
抽象的。双电子-电子共振（DEER）是一种测量顺磁中心之间距离的脉冲电子顺磁共振（EPR）技术。它利用基于重聚焦哈恩自旋回波的四脉冲序列。回波随脉冲序列长度2（τ1 + τ2）的增加而衰减，其中τ1和τ2是两个时间延迟。在DEER中，τ2的值由需要分辨的最长自旋间距离确定，并且调整τ1以最大化回波幅度并因此最大化灵敏度。我们的实验表明，对于典型的自旋中心（硝酰基，三苯甲基，Gd（III））在冷冻质子化溶剂稀释，最大的重聚焦回波幅度为给定的τ2既不是在很短的τ1（最小化脉冲序列长度），也不是在τ1 = τ2（最大化动态去耦为给定的总序列长度），而是在τ1值小于τ2。大规模的自旋动力学模拟，包括电子自旋和几百个相邻的质子再现实验观察到的行为几乎定量。他们表明，电子自旋退相是由溶剂质子通过它们之间的触发器耦合和它们与电子自旋的超精细耦合驱动的。
Abstract. Double electron–electron resonance (DEER) is a pulse electron paramagnetic resonance (EPR) technique that measures distances between paramagnetic centres. It utilizes a four-pulse sequence based on the refocused Hahn spin echo. The echo decays with increasing pulse sequence length 2(τ1 + τ2), where τ1 and τ2 are the two time delays. In DEER, the value of τ2 is determined by the longest inter-spin distance that needs to be resolved, and τ1 is adjusted to maximize the echo amplitude and thus sensitivity. We show experimentally that for typical spin centres (nitroxyl, trityl, Gd(III)) diluted in frozen protonated solvents, the largest refocused echo amplitude for a given τ2 is obtained neither at very short τ1 (which minimizes the pulse sequence length) nor at τ1 = τ2 (which maximizes dynamic decoupling for a given total sequence length), but rather at τ1 values smaller than τ2. Large-scale spin dynamics simulations including the electron spin and several hundred neighbouring protons reproduce the experimentally observed behaviour almost quantitatively. They show that electron spin dephasing is driven by solvent protons via the flip-flop coupling among themselves and their hyperfine couplings to the electron spin.
影响因子：
15
作者：
Yang, Zhongyu;Liu, Yangping;Borbat, Peter;Zweier, Jay L.;Freed, Jack H.;Hubbell, Wayne L.
通讯作者：
Hubbell, Wayne L.
影响因子：
16.6
作者：
Schmidt, Thomas;Walti, Marielle A.;Baber, James L.;Hustedt, Eric J.;Clore, G. Marius
通讯作者：
Clore, G. Marius
影响因子：
5.7
作者：
Spindler, Philipp E.;Waclawska, Izabela;Prisner, Thomas F.
通讯作者：
Prisner, Thomas F.