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第21讲-红外光谱中的官能团和指纹；磁核进动Lecture 21 - Functional Groups and Fingerprints in IR Spectroscopy; Precession of Magnetic Nuclei |
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| 课程网址: | http://videolectures.net/yalespan125bs2011_mcbride_lec21/ |
| 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: | Infrared spectroscopy provides information for analyzing molecular structure and for understanding bonding and dynamics. Although the normal modes of alkanes involve complex coordinated vibration of many atoms, the unusual strengths of multiple bonds give alkenes and alkynes distinctive stretching frequencies. The intensity of characteristic out-of-plane C-H bending peaks allows assignment of alkene configuration. Characteristic carbonyl stretching peaks in various functional groups demonstrate the importance of pi- and sigma-conjugation. The complex fingerprint region of IR spectra differentiates the subtle isomerism of polymorphic crystalline pharmaceuticals. A 90° phase lag between force and velocity explains the precession of tops and of magnetic nuclei in a magnetic field. Nuclear precession in the combination of a stationary magnet and a pulsed radio-frequency field can be visualized by means of the "rotating frame." |
| 关 键 词: | 红外光谱; 核进动; 官能团 |
| 课程来源: | 视频讲座网 |
| 数据采集: | 2021-11-13：zkj |
| 最后编审: | 2021-11-13：zkj |
| 阅读次数: | 35 |