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第23讲-抗磁各向异性和自旋分裂Lecture 23 - Diamagnetic Anisotropy and Spin-Spin Splitting |
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| 课程网址: | http://videolectures.net/yalespan125bs2011_mcbride_lec23/ |
| 主讲教师: | J. Michael McBride |
| 开课单位: | 耶鲁大学 |
| 开课时间: | 2014-08-19 |
| 课程语种: | 英语 |
| 中文简介: |  |
| 课程简介: | Through-space interaction between magnets of fixed strength and orientation averages to zero during random molecular tumbling, suggesting that the local field about a proton should be sensitive only to electrons that orbit about itself. The chemical shift can be sensitive to electrons orbiting elsewhere if the amount of orbiting varies with molecular orientation. This "diamagnetic anisotropy" is commonly used to rationalize the unusual chemical shifts of protons in acetylene and in aromatic and antiaromatic compounds. The other source of a proton's local field is nearby magnetic nuclei, which can be counted by the splitting multiplicity. Unlike chemical shift, which is measured in fractional units because it depends on the strength of the applied field, this spin-spin splitting (J), measured in Hz, is dependent only on molecular structure. J depends not on spatial proximity, but on orbital overlap, which, remarkably, is larger for anti- than for eclipsed conformations. |
| 关 键 词: | 抗磁各向异性; 分子结构; 异常化学位移 |
| 课程来源: | 视频讲座网 |
| 数据采集: | 2021-11-19：zkj |
| 最后编审: | 2021-11-19：zkj |
| 阅读次数: | 72 |