Håkansson Pär
School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK.
Phys Chem Chem Phys. 2017 Apr 19;19(16):10237-10254. doi: 10.1039/c6cp08394c.
Molecular dynamics and quantum chemistry methods are implemented to quantify nuclear spin-1/2 pair singlet-state relaxation rates for three molecular systems at low magnetic field and room temperature. Computational methodology is developed for weak interactions, particularly important for singlet states at low field. These include spin-rotation and spin-internal-motion effects, which describe the coupling of the spin-carrying nuclei to fluctuating local magnetic fields induced by the overall and internal molecular fluctuations, respectively. A high-dimensional tensor property surface using Kriging interpolation is developed to circumvent costly quantum-chemical calculations. Together with the intramolecular dipolar relaxation, all the simulated relaxation mechanisms are accounted for with a common theoretical framework. Comparison with experiment indicates that quantitative accuracy is obtained, sufficient to enable guidance in the molecular design of molecules with long-lived singlet order.
运用分子动力学和量子化学方法，对三个分子系统在低磁场和室温下的核自旋1/2对单重态弛豫速率进行了量化。针对弱相互作用开发了计算方法，这对低场单重态尤为重要。这些相互作用包括自旋-旋转和自旋-内部运动效应，分别描述了携带自旋的原子核与由整体分子涨落和内部分子涨落引起的波动局部磁场的耦合。利用克里金插值法开发了高维张量性质表面，以规避昂贵的量子化学计算。结合分子内偶极弛豫，所有模拟的弛豫机制都在一个通用的理论框架内进行了考虑。与实验结果的比较表明，获得了定量精度，足以指导具有长寿命单重态序的分子的分子设计。
