化学系专业外语课件7.Ultraviolet Spectroscopy培训资料.ppt

Ultraviolet Spectroscopy (紫外光谱) ultraviolet 紫外线的，紫外的 transparent 透明的，显然的，明晰的 nuclear magnetic resonance spectrum 核磁共振波谱 prism 棱镜 transition 跃迁，转变，转换 carbonyl 羰基 azo 含氮的 quantum 量子，量子论 symmetry 对称，匀称 theoretical 理论的 approximate 近似的，大约的 spectrophotometer 分光光度计 fluorescent 荧光的 monochromator 单色器，单色仪 deuterium 氘 tungsten 钨 diode 二极管 chromophore 发色团，生色团 wavelength 波长 unsaturated 不饱和的 substitution 代替，取代作用，代入法 auxochrome 助色团 alkoxy 烷氧基的 bathochromic effect 红移，减频效应 hypsochromic shift 蓝移，向短波长移 hyperchromic effect 增色效应 hypochromic effect 减色效应 Most organic molecules and functional groups are transparent in the portions of the electromagnetic spectrum which we call the ultraviolet (UV) and visible (VIS) regions-that is, the regions where wavelengths range from 190 nm to 800 nm. Consequently, absorption spectroscopy is of limited utility in this range of wavelengths. However, in some cases we can derive useful information from these regions of the spectrum. That information, when combined with the detail provided by infrared and nuclear magnetic resonance spectra, can lead to valuable structure proposals. 1. The Nature of Electronic Excitations When continuous radiation passes through a transparent material, a portion of the radiation may be absorbed. If that occurs, the residual radiation, when it is passed through a prism, yields a spectrum with gaps in it, called an absorption spectrum. As a result of energy absorption, atoms or molecules pass from a state of low energy (the initial, or ground state) to a state of higher energy (the excited state). The electromagnetic radiation which is absorbe