Knight shift tensors and π-spin densities in the organic metals αt-(BEDT-TTF)2I3 and (BEDT-TTF)2Cu(NCS)2
Knight shift tensors and π-spin densities in the organic metals αt-(BEDT-TTF)2I3 and (BEDT-TTF)2Cu(NCS)2
复制标题
有机金属 αt-(BEDT-TTF)2I3 和 (BEDT-TTF)2Cu(NCS)2 中的奈特位移张量和 π 自旋密度
DOI：
10.1007/bf03166055
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发表时间：
1991
影响因子：
1
通讯作者：
D. Schweitzer
中科院分区：
文献类型：
--
作者：
T. Klutz;I. Hennig;U. Haeberlen;D. Schweitzer
摘要纯BEDT-TTF 和有机金属αt-(BEDT-TTF)2I3 和(BEDT-TTF)2Cu(NCS)2 的13C-MASS 谱在νL = 68 MHz 下记录。各向同性位移和位移张量的主成分分别由中心带和旋转边带确定。对于纯 BEDT-TTF（一种抗磁绝缘体），测量到的位移是化学位移，而对于有机金属，它们是化学位移和奈特位移之和。在每种化合物中，位移按组分配给 BEDT-TTF 分子的内部、中间和外部碳。对于有机金属，讨论了实验位移与化学位移和奈特位移的分离。从奈特位移张量的各向异性部分可以推断出 BEDT-TTF 分子的碳和硫位置处的 π 自旋密度。结果是，不成对空穴的π自旋密度集中在BEDT-TTF分子的中心部分，即内部和中间的碳以及内部的硫上。有人认为电流密度也集中在 BEDT-TTF 分子的这一部分。
Abstract13C-MASS spectra of pure BEDT-TTF and of the organic metals αt-(BEDT-TTF)2I3 and (BEDT-TTF)2Cu(NCS)2 were recorded atνL = 68 MHz. Isotropic shifts and the principal components of the shift tensors were determined, respectively, from the center and spinning side bands. For pure BEDT-TTF which is a diamagnetic insolator, the measured shifts arechemical shifts while for the organic metals they are the sum of chemical and Knight shifts. In each of the compounds the shifts are assigned ingroups to theinner, middle andouter carbons of the BEDT-TTF molecule. For the organic metals the separation of the experimental shifts into chemical and Knight shifts is discussed. From the anisotropic part of the Knight shift tensors the π-spin densities at the carbon and sulphur positions of the BEDT-TTF molecule are inferred. The result is that the π-spin density of the unpaired hole is concentrated on the center part of the BEDT-TTF molecule, i.e., on the inner and middle carbons, and on the inner sulphurs. It is argued that the current density is concentrated on this part of the BEDT-TTF molecule as well.