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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Proton spin diffusion in polyethylene as a function of magic-angle spinning rate. A phenomenological approach
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Proton spin diffusion in polyethylene as a function of magic-angle spinning rate. A phenomenological approach

机译：质子在聚乙烯中的自旋扩散与魔角自旋速率的函数关系。现象学方法

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摘要

Starting from the phenomenological Bloembergen-Purcell-Pound equation a relation between magic-angle spinning (MAS) rate and spin diffusion is derived. The resulting model equation was fitted to observed spin diffusion versus MAS rate data obtained at 298 K on an high-density polyethylene sample, revealing a reduction in the effective spin diffusivity by (65 + 5) when increasing the MAS rate from 2 to 12 kHz. The same model equation enabled the rigid-lattice diffusivity to be estimated and was found to be only slightly higher, by approximately 10, compared to the spin diffusivity observed at the lowest MAS rate applied (2 kHz). Moreover, the model equation predicts a reduction in the effective spin diffusivity by more than 90 when increasing the MAS rate to more than 30 kHz.
机译：从现象学的Bloembergen-Purcell-Pound方程出发，推导了魔角自旋（MAS）速率与自旋扩散之间的关系。将所得模型方程拟合到在高密度聚乙烯样品上298 K处观测到的自旋扩散与MAS速率数据，结果显示，当MAS速率从2 kHz增加到12 kHz时，有效自旋扩散率降低了（65 + 5）%。相同的模型方程可以估计刚性晶格扩散率，并且发现与在施加的最低MAS速率（2 kHz）下观察到的自旋扩散率相比，仅略高约10%。此外，模型方程预测，当将 MAS 速率提高到 30 kHz 以上时，有效自旋扩散率将降低 90% 以上。

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