Understanding the electron spin relaxation properties of paramagnetic species is a fundamental requirement to use them as a probe to measure distances between sites in biomolecules by electron paramagnetic resonance (EPR) spectroscopy. Even though Ni(II) ion is an essential trace element for many species, relaxation properties are not well understood. Herein, the polycrystalline sample of Ni(II) ion magnetically diluted in Zn(Pyrazole)6(NO3)2 (Ni/ZPN) has been studied in detail by EPR spectroscopy to explore the electron spin relaxation time. Progressive continuous‐wave (CW) EPR power saturation study on Ni/ZPN at 300 K yielded 907 mW as the P1/2 value. The cavity constant (KQ) has been calculated using tempol in PVA‐BA glass matrix and the product of electron spin‐lattice relaxation time (T1) and spin–spin relaxation time (T2) for Ni/ZPN at 300 K has been reported for the first time.

中文翻译：

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Ni (II) 离子在六吡唑二硝酸锌 (II) 中的电子自旋弛豫时间在 300 K

了解顺磁性物质的电子自旋弛豫特性是使用它们作为探针通过电子顺磁共振 (EPR) 光谱测量生物分子中位点之间距离的基本要求。尽管 Ni(II) 离子是许多物种必不可少的微量元素，但其弛豫特性尚不清楚。在此，通过 EPR 光谱详细研究了在 Zn(Pyrazole)6(NO3)2 (Ni/ZPN) 中磁性稀释的 Ni(II) 离子的多晶样品，以探索电子自旋弛豫时间。Ni/ZPN 在 300 K 下的连续波 (CW) EPR 功率饱和研究产生 907 mW，作为 P1/2 值。