Direct conversion of EPR dipolar time evolution data to distance distributions
Direct conversion of EPR dipolar time evolution data to distance distributions
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DOI：
10.1006/jmre.2001.2498
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发表时间：
2002-03-01
影响因子：
2.2
通讯作者：
Godt, A
中科院分区：
文献类型：
--
作者：
Jeschke, G;Koch, A;Godt, A
由于电子自旋之间的偶极-偶极耦合引起的浅电子自旋回波包络调制提供了关于无序系统中自旋的径向分布函数的信息，而自旋对之间的角度相关性可以忽略不计。在这些条件下，在没有取向选择的情况下，可以通过壳因子分解对任意径向分布函数定量模拟偶极时间演化数据，即，通过分别对薄球壳进行取向平均并将所有球壳的信号相乘。对于小于5 nm的距离，壳层信号的线性叠加是足够的。偶极时间演化数据可以分为线性贡献和非线性背景。然后，线性贡献可以直接转换为径向分布函数。对于一系列的形状持久和灵活的双自由基的端到端的距离在2和5纳米之间，壳分解和直接转换的数据是在良好的协议彼此和力场计算的端到端的距离。忽略方向选择不会导致所确定的距离分布的显著失真。(C)2002 Elsevier Science（美国）。
Shallow electron spin echo envelope modulations due to dipole-dipole couplings between electron spins provide information on the radial distribution function of the spins in disordered systems while angular correlations between spin pairs are negligible. Under these conditions and in the absence of orientational selection, the dipolar time evolution data can be quantitatively simulated for arbitrary radial distribution functions by shell factorization, i.e., by performing the orientational average separately for thin spherical shells and multiplying the signals of all the shells. For distances below 5 nm, a linear superposition of the signals of the shells is sufficient. The dipolar time evolution data can be separated into this linear contribution and a nonlinear background. The linear contribution can then be converted directly to a radial distribution function. For a series of shape-persistent and flexible biradicals with end-to-end distances between 2 and 5 nm, shell factorization and direct conversion of the data are in good agreement with each other and with force-field computations of the end-to-end distances. The neglect of orientation selection does not cause significant distortions of the determined distance distributions. (C) 2002 Elsevier Science (USA).