Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK.
J Magn Reson. 2011 Aug;211(2):217-20. doi: 10.1016/j.jmr.2011.06.001. Epub 2011 Jun 13.
A numerical procedure is presented for mapping the vicinity of the null-space of the spin relaxation superoperator. The states populating this space, i.e. those with near-zero eigenvalues, of which the two-spin singlet is a well-studied example, are long-lived compared to the conventional T(1) and T(2) spin-relaxation times. The analysis of larger spin systems described herein reveals the presence of a significant number of other slowly relaxing states. A study of coupling topologies for n-spin systems (4≤n≤8) suggests the symmetry requirements for maximising the number of long-lived states.
提出了一种数值方法，用于绘制自旋弛豫超算符零空间的临近区域。填充这个空间的状态，即那些具有近零特征值的状态，与传统的 T(1)和 T(2)自旋弛豫时间相比，具有较长的寿命。本文对更大的自旋系统的分析揭示了存在大量其他缓慢弛豫的状态。对 n 自旋系统（4≤n≤8）的耦合拓扑结构的研究表明了最大化长寿命状态数量的对称要求。
