Study of the quantum properties and dissipative phenomena in molecular

The Magnetic Properties of Molecular Clusters attract considerable interest for the new physics involved and for the potential applications。在低温度下，这些分子的作用是作为个体量子纳米片，使其能够探测，在宏观尺度、量子和经典物理学之间的交叉。基本利益是两个磁性水平的程度的情况，量子力学现象可以作为隧道或相干性的地方。《量子动力学的基本问题》中的性别平等状况在水平之间产生。一个关键的问题是由磁性分子水平和作为喇叭的环境之间的耦合发挥作用的。这个项目的目标是实验性地验证特征量子能量水平和讨论在异常磁性放松现象和水平交叉之间可能的交互。为了这个目的，一个不同的模型成分被我们的团体和一些他们很好地合成 ... More 由化学家提供。表达者是Dimers（二核复合体）这种Cs3 Cr2 C19与X=Cl， Br， trimers（三核复合体）A3 Cu 3（PO 4）4与A=Ca、Sr、三聚链系统3CuCl 2·2dx、多核分子磁，如Mn 12、Fe 12、V15等，以及我们应用的各种互补技术，包括先进的晶体制备、核磁共振、电子自旋共振，中子散射，介子自旋放松，高场磁化作为良好的可持续性和特定的热量测量，与许多其他研究组进行合作。一种高场磁化技术已被应用于研究量子自旋系统的各种磁场依赖行为，通过将高场的温度降低到54吨，将温度降低到0.1 K。例如，我们在S=2/3 dimerized系统Cs3 Cr2 Cl 9中发现了三个受限制的磁场的成功相位转换到40吨。此外，在Fe 12分子磁铁中，它的形式是由12 Fe 3+（S=5/2）的有限链条组成的，我们可以看到五个等效场间隔的磁性步骤，并从能量水平交叉计算在有限自旋系统中离散量子状态。在这些例子中，我们讨论了能量水平的结构，即在水平交叉领域周围的金属状态下，放松现象将导致量子自旋动力学。此外，高频电子自旋共振（ESR）技术已应用于我们的目标，在宽温度范围降低至0.5 K，并使用高频源达到800 GHz。Examples are for the S=1/2 Heisenberg anttiferManagement magnetic chain system Cu-benzoate， Cu（C6H5COO）2·3 H2O and for the trimerized chain system 3 CuCl2·2 dx， in which ferManagement magnetic trimers consisting of three S=1/2 spins coupled antiferManagement agnetically in one dimension。These results partly have been published already。Less（低）

The magnetic properties of molecular clusters attract considerable interest for the new physics involved and for the potential applications. At low temperatures, these molecules act as individual quantum nanomagnets, enabling to probe, at the macroscopic scale, the crossover between quantum and classical physics. Of fundamental interest is the situation of degeneracy of two magnetic levels, where quantum mechanical phenomena such as tunneling or coherence can occur. The situation of degeneracy between levels raises fundamental problems of quantum dynamics. A crucial issue is the role played by the coupling between magnetic molecular levels and the environment such as phonons. The purpose of this project is to verify experimentally the characteristic quantum energy levels and discuss the possible interplay between the anomalous magnetic relaxation phenomena and the level-crossings. For this purpose, a variety of model substances were synthesized by our group and some of them were kindly … More supplied by chemists. The representatives are dimers (binuclear complexes) such as Cs3Cr2C19 with X=Cl, Br, trimers (trinuclear complexes) such as A3Cu3(PO4)4 with A=Ca, Sr, trimerized chain system 3CuCl2・2dx, polynuclear molecular magnets such as Mn12, Fe12, V15 and so on We applied various complementary techniques, including advanced crystal preparation, nuclear magnetic resonance, electron spin resonance, neutron scattering, muon spin relaxation, high field magnetization as well as susceptibility and specific heat measurements, in cooperation with many other research groups. A high-field magnetization technique was applied to study the field-dependent behaviors of various kind of quantum spin systems by applying high magnetic field up to 54 T at temperature down to 0.1 K.For example, we observed successive phase transitions at three restricted field regions up to 40T in the S=2/3 dimerized system Cs3Cr2Cl9. Also, in Fe12 molecular magnet which forms a finite chain ring consisting of 12 Fe3+(S=5/2) ions, we observed five magnetization steps with equal field spacing, arising from energy-level crossings for the discrete quantum states in the finite spin system. In these examples, we discussed the structure of the energy levels an d the relaxation phenomena due to quantum spin dynamics in the metastable states around the level-crossing fields. Also, a high-frequency electron spin resonance (ESR) technique was applied for our purpose, in the wide temperature range down to 0.5 K, using high frequency sources up to 800 GHz. Examples are for the S=1/2 Heisenberg anttiferromagnetic chain system Cu-benzoate, Cu(C6H5COO)2・3H2O and for the trimerized chain system 3CuCl2・2dx, in which ferromagnetic trimers consisting of three S=1/2 spins coupled antiferromagnetically in one dimension.These results partly have been published already. Less