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Applications of high frequency electron paramagnetic resonance on materials from quantum to classical regime.

机译:高频电子顺磁共振在从量子态到经典态的材料上的应用。

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摘要

This dissertation has focused on studying the electron spin dynamics in the quantum and classical limit and, most importantly, at the quantum-classical boundary. We have successfully used high frequency electron paramagnetic resonance (HF-EPR) techniques to characterize six paramagnetic materials with increasing number of unpaired electrons and molecular sizes. The samples studied are Mn2+-doped CdSe Quantum Dots (Mn:CdSe QDs), Na 20[Cu2Pd22PV12O60(OH) 8] (Cu2), Na12[X 2W18Cu3O66(H2O)3]·32H 2O (X = As, Sb) (Cu3), [Fe 7O4(O2CPh)11(dmem)2]·4MeCN (Fe7), [Mn7O4(pdpm)6(N 3)4](ClO4)2 (Mn7) and Na34[Mn19(OH)12(SiW10O 37)6]·115H2O (Mn19). Our results have illustrated that four samples including Mn:CdSe QDs, Cu2, Cu3 and Fe7 can be perfectly described with quantum mechanics while sample Mn19 behaves like a typical classical system. Most interestingly, sample Mn7 (S = 29/ 2) straddles the interface between the classical and quantum mechanical spin descriptions. Chapter 1 gives the motivation, overview and organization of this dissertation. Chapter 2 describes synthetic details of the materials studied, introduction of two HF-EPR spectrometers, as well as the computer simulation programs employed in this undertaking. Chapter 3 summarizes the HF-EPR studies of Mn:CdSe QDs, the first application of HF-EPR to magnetic QDs. Chapter 4 presents the structure and magnetic characterization of an octahedrally coordinated Cu(II) pair, a very rare bonding for Cu(II) ions. Chapter 5 reports the coherent manipulation of electron spins in an antiferromagnetically coupled spin triangle {Cu3} impregnated in free standing nanoporous silicon (NS) by using 240 GHz microwave pulses. Chapter 6 discusses continuous wave (cw) and pulsed HF-EPR measurements on an Fe-based magnetic cluster: Fe7. Chapter 7 describes the HF-EPR characterization of a high spin (S) compound, Mn7, whose properties straddle the interface between the classical and quantum mechanical spin descriptions. Chapter 8 reports the structure and magnetic properties of a novel, unique, discrete polyanion comprising a cationic, planar Mn19 assembly incorporated in a 60-tungsto-6-silicate. Finally, chapter 9 summarizes the major results and conclusions of this dissertation.
机译:本文主要研究在量子和经典极限,最重要的是在量子经典边界的电子自旋动力学。我们已经成功地使用了高频电子顺磁共振(HF-EPR)技术来表征六种顺磁性材料,这些材料具有越来越多的不成对电子和分子尺寸。研究的样品是Mn 2 + 掺杂的CdSe量子点( Mn:CdSe QDs ),Na 20 [Cu 2 Pd 22 PV 12 O 60 (OH) 8 ]( Cu 2 ),Na 12 [ X 2 W 18 Cu 3 O 66 (H 2 O) 3 ]·32H 2 O( X = As,Sb)( Cu 3 ),[Fe 7 O 4 (O < sub> 2 CPh) 11 (dmem) 2 ]·4MeCN( Fe 7 ), [Mn 7 O 4 (pdpm) 6 (N 3 4 ] (ClO 4 2 Mn 7 )和Na 34 [Mn < sub> 19 (OH) 12 (SiW 10 O 37 6 ]·115H < sub> 2 O( Mn 19 )。我们的结果表明,包括 Mn:CdSe QDs,Cu 2 ,Cu 3 和Fe 7 在内的四个样品可以被量子力学完美地描述,而样品 Mn 19 的行为就像典型的经典系统。最有趣的是,样品 Mn 7 S = 29 / 2 )跨越经典和量子机械自旋描述之间的接口。第1章给出了本文的动机,概述和组织结构。第2章介绍了所研究材料的综合细节,介绍了两个HF-EPR光谱仪,以及用于此任务的计算机模拟程序。第三章概述了 Mn:CdSe量子点的HF-EPR研究, HF-EPR在磁性量子点中的首次应用。第4章介绍了八面体配位的Cu(II)对的结构和磁性特征,这是Cu(II)离子非常罕见的键合。第5章介绍了使用240 GHz微波脉冲对浸渍在独立式纳米多孔硅(NS)中的反铁磁耦合自旋三角形{Cu 3 }中电子自旋的相干操纵。第6章讨论了在铁基磁团簇上的连续波(cw)和脉冲HF-EPR测量: Fe 7 第7章介绍了高铁的HF-EPR表征。自旋(S)化合物 Mn 7 ,其特性跨越经典和量子力学自旋描述之间的界面。第8章介绍了一种新颖独特的离散聚阴离子的结构和磁性,该阴离子包含结合在60钨6硅酸盐中的阳离子平面 Mn 19 组件。最后,第9章总结了本论文的主要成果和结论。

著录项

  • 作者

    Wang, Zhenxing.;

  • 作者单位

    The Florida State University.;

  • 授予单位 The Florida State University.;
  • 学科 Chemistry Molecular.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 151 p.
  • 总页数 151
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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